sys-libs/glibc: disable stripping for ld.so as well

Similar to how pthread must not be stripped in order to avoid breaking
gdb, ld.so must not be stripped in order to avoid breaking valgrind.

Closes: https://bugs.gentoo.org/920753
Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>
Signed-off-by: Sam James <sam@gentoo.org>

2 files changed, 3402 insertions, 0 deletions

diff --git a/sys-libs/glibc/glibc-2.37-r9.ebuild b/sys-libs/glibc/glibc-2.37-r9.ebuild
new file mode 100644
index 000000000000..31748a86fe4b
--- /dev/null
+++ b/sys-libs/glibc/glibc-2.37-r9.ebuild
@@ -0,0 +1,1684 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+# Bumping notes: https://wiki.gentoo.org/wiki/Project:Toolchain/sys-libs/glibc
+# Please read & adapt the page as necessary if obsolete.
+
+PYTHON_COMPAT=( python3_{9..11} )
+TMPFILES_OPTIONAL=1
+
+inherit python-any-r1 prefix preserve-libs toolchain-funcs flag-o-matic gnuconfig \
+	multilib systemd multiprocessing tmpfiles
+
+DESCRIPTION="GNU libc C library"
+HOMEPAGE="https://www.gnu.org/software/libc/"
+LICENSE="LGPL-2.1+ BSD HPND ISC inner-net rc PCRE"
+SLOT="2.2"
+
+EMULTILIB_PKG="true"
+
+# Gentoo patchset (ignored for live ebuilds)
+PATCH_VER=11
+PATCH_DEV=dilfridge
+
+# gcc mulitilib bootstrap files version
+GCC_BOOTSTRAP_VER=20201208
+
+# systemd integration version
+GLIBC_SYSTEMD_VER=20210729
+
+# Minimum kernel version that glibc requires
+MIN_KERN_VER="3.2.0"
+
+# Minimum pax-utils version needed (which contains any new syscall changes for
+# its seccomp filter!). Please double check this!
+MIN_PAX_UTILS_VER="1.3.3"
+
+if [[ ${PV} == 9999* ]]; then
+	inherit git-r3
+else
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86"
+	SRC_URI="mirror://gnu/glibc/${P}.tar.xz"
+	SRC_URI+=" https://dev.gentoo.org/~${PATCH_DEV}/distfiles/${P}-patches-${PATCH_VER}.tar.xz"
+fi
+
+SRC_URI+=" multilib-bootstrap? ( https://dev.gentoo.org/~dilfridge/distfiles/gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz )"
+SRC_URI+=" systemd? ( https://gitweb.gentoo.org/proj/toolchain/glibc-systemd.git/snapshot/glibc-systemd-${GLIBC_SYSTEMD_VER}.tar.gz )"
+
+IUSE="audit caps cet compile-locales +crypt custom-cflags doc gd hash-sysv-compat headers-only +multiarch multilib multilib-bootstrap nscd perl profile selinux +ssp stack-realign +static-libs suid systemd systemtap test vanilla"
+
+# Here's how the cross-compile logic breaks down ...
+#  CTARGET - machine that will target the binaries
+#  CHOST   - machine that will host the binaries
+#  CBUILD  - machine that will build the binaries
+# If CTARGET != CHOST, it means you want a libc for cross-compiling.
+# If CHOST != CBUILD, it means you want to cross-compile the libc.
+#  CBUILD = CHOST = CTARGET    - native build/install
+#  CBUILD != (CHOST = CTARGET) - cross-compile a native build
+#  (CBUILD = CHOST) != CTARGET - libc for cross-compiler
+#  CBUILD != CHOST != CTARGET  - cross-compile a libc for a cross-compiler
+# For install paths:
+#  CHOST = CTARGET  - install into /
+#  CHOST != CTARGET - install into /usr/CTARGET/
+#
+export CBUILD=${CBUILD:-${CHOST}}
+export CTARGET=${CTARGET:-${CHOST}}
+if [[ ${CTARGET} == ${CHOST} ]] ; then
+	if [[ ${CATEGORY} == cross-* ]] ; then
+		export CTARGET=${CATEGORY#cross-}
+	fi
+fi
+
+# Note [Disable automatic stripping]
+# Disabling automatic stripping for a few reasons:
+# - portage's attempt to strip breaks non-native binaries at least on
+#   arm: bug #697428
+# - portage's attempt to strip libpthread.so.0 breaks gdb thread
+#   enumeration: bug #697910. This is quite subtle:
+#   * gdb uses glibc's libthread_db-1.0.so to enumerate threads.
+#   * libthread_db-1.0.so needs access to libpthread.so.0 local symbols
+#     via 'ps_pglobal_lookup' symbol defined in gdb.
+#   * 'ps_pglobal_lookup' uses '.symtab' section table to resolve all
+#     known symbols in 'libpthread.so.0'. Specifically 'nptl_version'
+#     (unexported) is used to sanity check compatibility before enabling
+#     debugging.
+#     Also see https://sourceware.org/gdb/wiki/FAQ#GDB_does_not_see_any_threads_besides_the_one_in_which_crash_occurred.3B_or_SIGTRAP_kills_my_program_when_I_set_a_breakpoint
+#   * normal 'strip' command trims '.symtab'
+#   Thus our main goal here is to prevent 'libpthread.so.0' from
+#   losing it's '.symtab' entries.
+# - similarly, valgrind requires knowledge about symbols in ld.so:
+#	bug #920753
+# As Gentoo's strip does not allow us to pass less aggressive stripping
+# options and does not check the machine target we strip selectively.
+
+# We need a new-enough binutils/gcc to match upstream baseline.
+# Also we need to make sure our binutils/gcc supports TLS,
+# and that gcc already contains the hardened patches.
+# Lastly, let's avoid some openssh nastiness, bug 708224, as
+# convenience to our users.
+
+IDEPEND="
+	!compile-locales? ( sys-apps/locale-gen )
+"
+BDEPEND="
+	${PYTHON_DEPS}
+	>=app-misc/pax-utils-${MIN_PAX_UTILS_VER}
+	sys-devel/bison
+	compile-locales? ( sys-apps/locale-gen )
+	doc? (
+		dev-lang/perl
+		sys-apps/texinfo
+	)
+	test? (
+		dev-lang/perl
+		>=net-dns/libidn2-2.3.0
+	)
+"
+COMMON_DEPEND="
+	gd? ( media-libs/gd:2= )
+	nscd? ( selinux? (
+		audit? ( sys-process/audit )
+		caps? ( sys-libs/libcap )
+	) )
+	suid? ( caps? ( sys-libs/libcap ) )
+	selinux? ( sys-libs/libselinux )
+	systemtap? ( dev-util/systemtap )
+"
+DEPEND="${COMMON_DEPEND}
+"
+RDEPEND="${COMMON_DEPEND}
+	!<app-misc/pax-utils-${MIN_PAX_UTILS_VER}
+	perl? ( dev-lang/perl )
+"
+
+RESTRICT="!test? ( test )"
+
+if [[ ${CATEGORY} == cross-* ]] ; then
+	BDEPEND+=" !headers-only? (
+		>=${CATEGORY}/binutils-2.27
+		>=${CATEGORY}/gcc-6.2
+	)"
+	[[ ${CATEGORY} == *-linux* ]] && DEPEND+=" ${CATEGORY}/linux-headers"
+else
+	BDEPEND+="
+		>=sys-devel/binutils-2.27
+		>=sys-devel/gcc-6.2
+	"
+	DEPEND+=" virtual/os-headers "
+	RDEPEND+="
+		>=net-dns/libidn2-2.3.0
+		vanilla? ( !sys-libs/timezone-data )
+	"
+	PDEPEND+=" !vanilla? ( sys-libs/timezone-data )"
+fi
+
+# Ignore tests whitelisted below
+GENTOO_GLIBC_XFAIL_TESTS="${GENTOO_GLIBC_XFAIL_TESTS:-yes}"
+
+# The following tests fail due to the Gentoo build system and are thus
+# executed but ignored:
+XFAIL_TEST_LIST=(
+	# buggy test, assumes /dev/ and /dev/null on a single filesystem
+	# 'mount --bind /dev/null /chroot/dev/null' breaks it.
+	# https://sourceware.org/PR25909
+	tst-support_descriptors
+
+	# The following tests fail only inside portage
+	# https://bugs.gentoo.org/831267
+	tst-system
+	tst-strerror
+	tst-strsignal
+)
+
+XFAIL_NSPAWN_TEST_LIST=(
+	# These tests need to be adapted to handle EPERM/ENOSYS(?) properly
+	# upstream, as systemd-nspawn's default seccomp whitelist is too strict.
+	# https://sourceware.org/PR30603
+	test-errno-linux
+	tst-bz21269
+	tst-mlock2
+	tst-ntp_gettime
+	tst-ntp_gettime-time64
+	tst-ntp_gettimex
+	tst-ntp_gettimex-time64
+	tst-pkey
+	tst-process_mrelease
+	tst-adjtime
+	tst-adjtime-time64
+	tst-clock2
+	tst-clock2-time64
+
+	# These fail if --suppress-sync and/or low priority is set
+	tst-sync_file_range
+	tst-sched1
+	test-errno
+)
+
+#
+# Small helper functions
+#
+
+dump_build_environment() {
+	einfo ==== glibc build environment ========================================================
+	local v
+	for v in ABI CBUILD CHOST CTARGET CBUILD_OPT CTARGET_OPT CC CXX CPP LD {AS,C,CPP,CXX,LD}FLAGS MAKEINFO NM AR AS STRIP RANLIB OBJCOPY STRINGS OBJDUMP READELF; do
+		einfo " $(printf '%15s' ${v}:)   ${!v}"
+	done
+	einfo =====================================================================================
+}
+
+is_crosscompile() {
+	[[ ${CHOST} != ${CTARGET} ]]
+}
+
+just_headers() {
+	is_crosscompile && use headers-only
+}
+
+alt_prefix() {
+	is_crosscompile && echo /usr/${CTARGET}
+}
+
+# This prefix is applicable to CHOST when building against this
+# glibc. It is baked into the library at configure time.
+host_eprefix() {
+	is_crosscompile || echo "${EPREFIX}"
+}
+
+# This prefix is applicable to CBUILD when building against this
+# glibc. It determines the destination path at install time.
+build_eprefix() {
+	is_crosscompile && echo "${EPREFIX}"
+}
+
+# We need to be able to set alternative headers for compiling for non-native
+# platform. Will also become useful for testing kernel-headers without screwing
+# up the whole system.
+alt_headers() {
+	echo ${ALT_HEADERS:=$(alt_prefix)/usr/include}
+}
+
+alt_build_headers() {
+	if [[ -z ${ALT_BUILD_HEADERS} ]] ; then
+		ALT_BUILD_HEADERS="$(host_eprefix)$(alt_headers)"
+		if tc-is-cross-compiler ; then
+			ALT_BUILD_HEADERS=${SYSROOT}$(alt_headers)
+			if [[ ! -e ${ALT_BUILD_HEADERS}/linux/version.h ]] ; then
+				local header_path=$(echo '#include <linux/version.h>' | $(tc-getCPP ${CTARGET}) ${CFLAGS} 2>&1 | grep -o '[^"]*linux/version.h')
+				ALT_BUILD_HEADERS=${header_path%/linux/version.h}
+			fi
+		fi
+	fi
+	echo "${ALT_BUILD_HEADERS}"
+}
+
+alt_libdir() {
+	echo $(alt_prefix)/$(get_libdir)
+}
+alt_usrlibdir() {
+	echo $(alt_prefix)/usr/$(get_libdir)
+}
+
+builddir() {
+	echo "${WORKDIR}/build-${ABI}-${CTARGET}-$1"
+}
+
+do_compile_test() {
+	local ret save_cflags=${CFLAGS}
+	CFLAGS+=" $1"
+	shift
+
+	pushd "${T}" >/dev/null
+
+	rm -f glibc-test*
+	printf '%b' "$*" > glibc-test.c
+
+	# We assume CC is already set up.
+	nonfatal emake glibc-test
+	ret=$?
+
+	popd >/dev/null
+
+	CFLAGS=${save_cflags}
+	return ${ret}
+}
+
+do_run_test() {
+	local ret
+
+	if [[ ${MERGE_TYPE} == "binary" ]] ; then
+		# ignore build failures when installing a binary package #324685
+		do_compile_test "" "$@" 2>/dev/null || return 0
+	else
+		if ! do_compile_test "" "$@" ; then
+			ewarn "Simple build failed ... assuming this is desired #324685"
+			return 0
+		fi
+	fi
+
+	pushd "${T}" >/dev/null
+
+	./glibc-test
+	ret=$?
+	rm -f glibc-test*
+
+	popd >/dev/null
+
+	return ${ret}
+}
+
+setup_target_flags() {
+	# This largely mucks with compiler flags.  None of which should matter
+	# when building up just the headers.
+	just_headers && return 0
+
+	case $(tc-arch) in
+		x86)
+			# -march needed for #185404 #199334
+			# TODO: When creating the first glibc cross-compile, this test will
+			# always fail as it does a full link which in turn requires glibc.
+			# Probably also applies when changing multilib profile settings (e.g.
+			# enabling x86 when the profile was amd64-only previously).
+			# We could change main to _start and pass -nostdlib here so that we
+			# only test the gcc code compilation.  Or we could do a compile and
+			# then look for the symbol via scanelf.
+			if ! do_compile_test "" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n'; then
+				local t=${CTARGET_OPT:-${CTARGET}}
+				t=${t%%-*}
+				filter-flags '-march=*'
+				export CFLAGS="-march=${t} ${CFLAGS}"
+				einfo "Auto adding -march=${t} to CFLAGS #185404"
+			fi
+			# For compatibility with older binaries at slight performance cost.
+			use stack-realign && export CFLAGS+=" -mstackrealign"
+		;;
+		amd64)
+			# -march needed for #185404 #199334
+			# TODO: See cross-compile issues listed above for x86.
+			if [[ ${ABI} == x86 ]]; then
+				if ! do_compile_test "${CFLAGS_x86}" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n'; then
+					local t=${CTARGET_OPT:-${CTARGET}}
+					t=${t%%-*}
+					# Normally the target is x86_64-xxx, so turn that into the -march that
+					# gcc actually accepts. #528708
+					[[ ${t} == "x86_64" ]] && t="x86-64"
+					filter-flags '-march=*'
+					# ugly, ugly, ugly.  ugly.
+					CFLAGS_x86=$(CFLAGS=${CFLAGS_x86} filter-flags '-march=*'; echo "${CFLAGS}")
+					export CFLAGS_x86="${CFLAGS_x86} -march=${t}"
+					einfo "Auto adding -march=${t} to CFLAGS_x86 #185404 (ABI=${ABI})"
+				fi
+				# For compatibility with older binaries at slight performance cost.
+				use stack-realign && export CFLAGS_x86+=" -mstackrealign"
+
+				# Workaround for bug #823780.
+				# Need to save/restore CC because earlier on, we stuff it full of CFLAGS, and tc-getCPP doesn't like that.
+				CC_mangled=${CC}
+				CC=${glibc__GLIBC_CC}
+				if tc-is-gcc && (($(gcc-major-version) == 11)) && (($(gcc-minor-version) <= 2)) && (($(gcc-micro-version) == 0)) ; then
+					export CFLAGS_x86="${CFLAGS_x86} -mno-avx512f"
+					einfo "Auto adding -mno-avx512f to CFLAGS_x86 for buggy GCC version (bug #823780) (ABI=${ABI})"
+				fi
+				CC=${CC_mangled}
+			fi
+		;;
+		mips)
+			# The mips abi cannot support the GNU style hashes. #233233
+			filter-ldflags -Wl,--hash-style=gnu -Wl,--hash-style=both
+		;;
+		ppc|ppc64)
+			# Many arch-specific implementations do not work on ppc with
+			# cache-block not equal to 128 bytes. This breaks memset:
+			#   https://sourceware.org/PR26522
+			#   https://bugs.gentoo.org/737996
+			# Use default -mcpu=. For ppc it means non-multiarch setup.
+			filter-flags '-mcpu=*'
+		;;
+		sparc)
+			# Both sparc and sparc64 can use -fcall-used-g6.  -g7 is bad, though.
+			filter-flags "-fcall-used-g7"
+			append-flags "-fcall-used-g6"
+
+			local cpu
+			case ${CTARGET} in
+			sparc64-*)
+				cpu="sparc64"
+				case $(get-flag mcpu) in
+				v9)
+					# We need to force at least v9a because the base build doesn't
+					# work with just v9.
+					# https://sourceware.org/bugzilla/show_bug.cgi?id=19477
+					append-flags "-Wa,-xarch=v9a"
+					;;
+				esac
+				;;
+			sparc-*)
+				case $(get-flag mcpu) in
+				v8|supersparc|hypersparc|leon|leon3)
+					cpu="sparcv8"
+					;;
+				*)
+					cpu="sparcv9"
+					;;
+				esac
+			;;
+			esac
+			[[ -n ${cpu} ]] && CTARGET_OPT="${cpu}-${CTARGET#*-}"
+		;;
+	esac
+}
+
+setup_flags() {
+	# Make sure host make.conf doesn't pollute us
+	if is_crosscompile || tc-is-cross-compiler ; then
+		CHOST=${CTARGET} strip-unsupported-flags
+	fi
+
+	# Store our CFLAGS because it's changed depending on which CTARGET
+	# we are building when pulling glibc on a multilib profile
+	CFLAGS_BASE=${CFLAGS_BASE-${CFLAGS}}
+	CFLAGS=${CFLAGS_BASE}
+	CXXFLAGS_BASE=${CXXFLAGS_BASE-${CXXFLAGS}}
+	CXXFLAGS=${CXXFLAGS_BASE}
+	ASFLAGS_BASE=${ASFLAGS_BASE-${ASFLAGS}}
+	ASFLAGS=${ASFLAGS_BASE}
+
+	# Allow users to explicitly avoid flag sanitization via
+	# USE=custom-cflags.
+	if ! use custom-cflags; then
+		# Over-zealous CFLAGS can often cause problems.  What may work for one
+		# person may not work for another.  To avoid a large influx of bugs
+		# relating to failed builds, we strip most CFLAGS out to ensure as few
+		# problems as possible.
+		strip-flags
+		# Lock glibc at -O2; we want to be conservative here.
+		filter-flags '-O?'
+		append-flags -O2
+	fi
+
+	strip-unsupported-flags
+	filter-lto
+	filter-flags -m32 -m64 '-mabi=*'
+
+	# glibc aborts if rpath is set by LDFLAGS
+	filter-ldflags '-Wl,-rpath=*'
+
+	# ld can't use -r & --relax at the same time, bug #788901
+	# https://sourceware.org/PR27837
+	filter-ldflags '-Wl,--relax'
+
+	# some weird software relies on sysv hashes in glibc, bug 863863, bug 864100
+	# we have to do that here already so mips can filter it out again :P
+	if use hash-sysv-compat ; then
+		append-ldflags '-Wl,--hash-style=both'
+	fi
+
+	# #492892
+	filter-flags -frecord-gcc-switches
+
+	# #898098
+	filter-flags -fno-builtin
+
+	# #829583
+	filter-lfs-flags
+
+	unset CBUILD_OPT CTARGET_OPT
+	if use multilib ; then
+		CTARGET_OPT=$(get_abi_CTARGET)
+		[[ -z ${CTARGET_OPT} ]] && CTARGET_OPT=$(get_abi_CHOST)
+	fi
+
+	setup_target_flags
+
+	if [[ -n ${CTARGET_OPT} && ${CBUILD} == ${CHOST} ]] && ! is_crosscompile; then
+		CBUILD_OPT=${CTARGET_OPT}
+	fi
+
+	# glibc's headers disallow -O0 and fail at build time:
+	#  include/libc-symbols.h:75:3: #error "glibc cannot be compiled without optimization"
+	# https://sourceware.org/glibc/wiki/FAQ#Why_do_I_get:.60.23error_.22glibc_cannot_be_compiled_without_optimization.22.27.2C_when_trying_to_compile_GNU_libc_with_GNU_CC.3F
+	replace-flags -O0 -O1
+
+	# glibc handles this internally already where it's appropriate;
+	# can't always have SSP when we're the ones setting it up, etc
+	filter-flags '-fstack-protector*'
+
+	# Similar issues as with SSP. Can't inject yourself that early.
+	filter-flags '-fsanitize=*'
+
+	# See end of bug #830454; we handle this via USE=cet
+	filter-flags '-fcf-protection=*'
+
+	# When bootstrapping, we may have a situation where
+	# CET-enabled gcc from seed is used to build CET-disabled
+	# glibc. As such, gcc implicitly enables CET if no
+	# -fcf-protection flag is passed. For a typical package it
+	# should not be a problem, but for glibc it matters as it is
+	# dealing with CET in ld.so. So if CET is supposed to be
+	# disabled for glibc, be explicit about it.
+	if (use amd64 || use x86) && ! use cet; then
+		append-flags '-fcf-protection=none'
+	fi
+}
+
+use_multiarch() {
+	# Allow user to disable runtime arch detection in multilib.
+	use multiarch || return 1
+	# Make sure binutils is new enough to support indirect functions,
+	# #336792. This funky sed supports gold and bfd linkers.
+	local bver nver
+	bver=$($(tc-getLD ${CTARGET}) -v | sed -n -r '1{s:[^0-9]*::;s:^([0-9.]*).*:\1:;p}')
+	case $(tc-arch ${CTARGET}) in
+	amd64|x86) nver="2.20" ;;
+	arm)       nver="2.22" ;;
+	hppa)      nver="2.23" ;;
+	ppc|ppc64) nver="2.20" ;;
+	# ifunc support was added in 2.23, but glibc also needs
+	# machinemode which is in 2.24.
+	s390)      nver="2.24" ;;
+	sparc)     nver="2.21" ;;
+	*)         return 1 ;;
+	esac
+	ver_test ${bver} -ge ${nver}
+}
+
+# Setup toolchain variables that had historically been defined in the
+# profiles for these archs.
+setup_env() {
+	# silly users
+	unset LD_RUN_PATH
+	unset LD_ASSUME_KERNEL
+
+	if is_crosscompile || tc-is-cross-compiler ; then
+		multilib_env ${CTARGET_OPT:-${CTARGET}}
+
+		if ! use multilib ; then
+			MULTILIB_ABIS=${DEFAULT_ABI}
+		else
+			MULTILIB_ABIS=${MULTILIB_ABIS:-${DEFAULT_ABI}}
+		fi
+
+		# If the user has CFLAGS_<CTARGET> in their make.conf, use that,
+		# and fall back on CFLAGS.
+		local VAR=CFLAGS_${CTARGET//[-.]/_}
+		CFLAGS=${!VAR-${CFLAGS}}
+		einfo " $(printf '%15s' 'Manual CFLAGS:')   ${CFLAGS}"
+	fi
+
+	setup_flags
+
+	export ABI=${ABI:-${DEFAULT_ABI:-default}}
+
+	if just_headers ; then
+		# Avoid mixing host's CC and target's CFLAGS_${ABI}:
+		# At this bootstrap stage we have only binutils for
+		# target but not compiler yet.
+		einfo "Skip CC ABI injection. We can't use (cross-)compiler yet."
+		return 0
+	fi
+
+	# Glibc does not work with gold (for various reasons) #269274.
+	tc-ld-disable-gold
+
+	if use doc ; then
+		export MAKEINFO=makeinfo
+	else
+		export MAKEINFO=/dev/null
+	fi
+
+	# Reset CC and CXX to the value at start of emerge
+	export CC=${glibc__ORIG_CC:-${CC:-$(tc-getCC ${CTARGET})}}
+	export CXX=${glibc__ORIG_CXX:-${CXX:-$(tc-getCXX ${CTARGET})}}
+
+	# and make sure glibc__ORIG_CC and glibc__ORIG_CXX is defined now.
+	export glibc__ORIG_CC=${CC}
+	export glibc__ORIG_CXX=${CXX}
+
+	if tc-is-clang && ! use custom-cflags && ! is_crosscompile ; then
+		export glibc__force_gcc=yes
+		# once this is toggled on, it needs to stay on, since with CPP manipulated
+		# tc-is-clang does not work correctly anymore...
+	fi
+
+	if [[ ${glibc__force_gcc} == "yes" ]] ; then
+		# If we are running in an otherwise clang/llvm environment, we need to
+		# recover the proper gcc and binutils settings here, at least until glibc
+		# is finally building with clang. So let's override everything that is
+		# set in the clang profiles.
+		# Want to shoot yourself into the foot? Set USE=custom-cflags, that's always
+		# a good start into that direction.
+		# Also, if you're crosscompiling, let's assume you know what you are doing.
+		# Hopefully.
+		# Last, we need the settings of the *build* environment, not of the
+		# target environment...
+
+		local current_binutils_path=$(env ROOT="${BROOT}" binutils-config -B)
+		local current_gcc_path=$(env ROOT="${BROOT}" gcc-config -B)
+		einfo "Overriding clang configuration, since it won't work here"
+
+		export CC="${current_gcc_path}/gcc"
+		export CPP="${current_gcc_path}/cpp"
+		export CXX="${current_gcc_path}/g++"
+		export LD="${current_binutils_path}/ld.bfd"
+		export AR="${current_binutils_path}/ar"
+		export AS="${current_binutils_path}/as"
+		export NM="${current_binutils_path}/nm"
+		export STRIP="${current_binutils_path}/strip"
+		export RANLIB="${current_binutils_path}/ranlib"
+		export OBJCOPY="${current_binutils_path}/objcopy"
+		export STRINGS="${current_binutils_path}/strings"
+		export OBJDUMP="${current_binutils_path}/objdump"
+		export READELF="${current_binutils_path}/readelf"
+		export ADDR2LINE="${current_binutils_path}/addr2line"
+
+		# do we need to also do flags munging here? yes! at least...
+		filter-flags '-fuse-ld=*'
+		filter-flags '-D_FORTIFY_SOURCE=*'
+
+	else
+
+		# this is the "normal" case
+
+		export CC="$(tc-getCC ${CTARGET})"
+		export CXX="$(tc-getCXX ${CTARGET})"
+
+		# Always use tuple-prefixed toolchain. For non-native ABI glibc's configure
+		# can't detect them automatically due to ${CHOST} mismatch and fallbacks
+		# to unprefixed tools. Similar to multilib.eclass:multilib_toolchain_setup().
+		export NM="$(tc-getNM ${CTARGET})"
+		export READELF="$(tc-getREADELF ${CTARGET})"
+
+	fi
+
+	# We need to export CFLAGS with abi information in them because glibc's
+	# configure script checks CFLAGS for some targets (like mips).  Keep
+	# around the original clean value to avoid appending multiple ABIs on
+	# top of each other. (Why does the comment talk about CFLAGS if the code
+	# acts on CC?)
+	export glibc__GLIBC_CC=${CC}
+	export glibc__GLIBC_CXX=${CXX}
+
+	export glibc__abi_CFLAGS="$(get_abi_CFLAGS)"
+
+	# CFLAGS can contain ABI-specific flags like -mfpu=neon, see bug #657760
+	# To build .S (assembly) files with the same ABI-specific flags
+	# upstream currently recommends adding CFLAGS to CC/CXX:
+	#    https://sourceware.org/PR23273
+	# Note: Passing CFLAGS via CPPFLAGS overrides glibc's arch-specific CFLAGS
+	# and breaks multiarch support. See 659030#c3 for an example.
+	# The glibc configure script doesn't properly use LDFLAGS all the time.
+	export CC="${glibc__GLIBC_CC} ${glibc__abi_CFLAGS} ${CFLAGS} ${LDFLAGS}"
+
+	# Some of the tests are written in C++, so we need to force our multlib abis in, bug 623548
+	export CXX="${glibc__GLIBC_CXX} ${glibc__abi_CFLAGS} ${CFLAGS}"
+
+	if is_crosscompile; then
+		# Assume worst-case bootstrap: glibc is buil first time
+		# when ${CTARGET}-g++ is not available yet. We avoid
+		# building auxiliary programs that require C++: bug #683074
+		# It should not affect final result.
+		export libc_cv_cxx_link_ok=no
+		# The line above has the same effect. We set CXX explicitly
+		# to make build logs less confusing.
+		export CXX=
+	fi
+}
+
+foreach_abi() {
+	setup_env
+
+	local ret=0
+	local abilist=""
+	if use multilib ; then
+		abilist=$(get_install_abis)
+	else
+		abilist=${DEFAULT_ABI}
+	fi
+	local -x ABI
+	for ABI in ${abilist:-default} ; do
+		setup_env
+		einfo "Running $1 for ABI ${ABI}"
+		$1
+		: $(( ret |= $? ))
+	done
+	return ${ret}
+}
+
+glibc_banner() {
+	local b="Gentoo ${PVR}"
+	[[ -n ${PATCH_VER} ]] && ! use vanilla && b+=" (patchset ${PATCH_VER})"
+	echo "${b}"
+}
+
+# The following Kernel version handling functions are mostly copied from portage
+# source. It's better not to use linux-info.eclass here since a) it adds too
+# much magic, see bug 326693 for some of the arguments, and b) some of the
+# functions are just not provided.
+
+g_get_running_KV() {
+	uname -r
+	return $?
+}
+
+g_KV_major() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	echo "${KV%%.*}"
+}
+
+g_KV_minor() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	KV=${KV#*.}
+	echo "${KV%%.*}"
+}
+
+g_KV_micro() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	KV=${KV#*.*.}
+	echo "${KV%%[^[:digit:]]*}"
+}
+
+g_KV_to_int() {
+	[[ -z $1 ]] && return 1
+	local KV_MAJOR=$(g_KV_major "$1")
+	local KV_MINOR=$(g_KV_minor "$1")
+	local KV_MICRO=$(g_KV_micro "$1")
+	local KV_int=$(( KV_MAJOR * 65536 + KV_MINOR * 256 + KV_MICRO ))
+
+	# We make version 2.2.0 the minimum version we will handle as
+	# a sanity check ... if its less, we fail ...
+	if [[ ${KV_int} -ge 131584 ]] ; then
+		echo "${KV_int}"
+		return 0
+	fi
+	return 1
+}
+
+g_int_to_KV() {
+	local version=$1 major minor micro
+	major=$((version / 65536))
+	minor=$(((version % 65536) / 256))
+	micro=$((version % 256))
+	echo ${major}.${minor}.${micro}
+}
+
+eend_KV() {
+	[[ $(g_KV_to_int $1) -ge $(g_KV_to_int $2) ]]
+	eend $?
+}
+
+get_kheader_version() {
+	printf '#include <linux/version.h>\nLINUX_VERSION_CODE\n' | \
+	$(tc-getCPP ${CTARGET}) -I "$(build_eprefix)$(alt_build_headers)" - | \
+	tail -n 1
+}
+
+# We collect all sanity checks here. Consistency is not guranteed between
+# pkg_ and src_ phases, so we call this function both in pkg_pretend and in
+# src_unpack.
+sanity_prechecks() {
+	# Prevent native builds from downgrading
+	if [[ ${MERGE_TYPE} != "buildonly" ]] && \
+	   [[ -z ${ROOT} ]] && \
+	   [[ ${CBUILD} == ${CHOST} ]] && \
+	   [[ ${CHOST} == ${CTARGET} ]] ; then
+
+		# The high rev # is to allow people to downgrade between -r#
+		# versions. We want to block 2.20->2.19, but 2.20-r3->2.20-r2
+		# should be fine. Hopefully we never actually use a r# this
+		# high.
+		if has_version ">${CATEGORY}/${P}-r10000" ; then
+			eerror "Sanity check to keep you from breaking your system:"
+			eerror " Downgrading glibc is not supported and a sure way to destruction."
+			[[ ${I_ALLOW_TO_BREAK_MY_SYSTEM} = yes ]] || die "Aborting to save your system."
+		fi
+
+		if ! do_run_test '#include <unistd.h>\n#include <sys/syscall.h>\nint main(){return syscall(1000)!=-1;}\n' ; then
+			eerror "Your old kernel is broken. You need to update it to a newer"
+			eerror "version as syscall(<bignum>) will break. See bug 279260."
+			die "Old and broken kernel."
+		fi
+	fi
+
+	if [[ ${CTARGET} == i386-* ]] ; then
+		eerror "i386 CHOSTs are no longer supported."
+		eerror "Chances are you don't actually want/need i386."
+		eerror "Please read https://www.gentoo.org/doc/en/change-chost.xml"
+		die "Please fix your CHOST"
+	fi
+
+	if [[ -e /proc/xen ]] && [[ $(tc-arch) == "x86" ]] && ! is-flag -mno-tls-direct-seg-refs ; then
+		ewarn "You are using Xen but don't have -mno-tls-direct-seg-refs in your CFLAGS."
+		ewarn "This will result in a 50% performance penalty when running with a 32bit"
+		ewarn "hypervisor, which is probably not what you want."
+	fi
+
+	# ABI-specific checks follow here. Hey, we have a lot more specific conditions that
+	# we test for...
+	if ! is_crosscompile ; then
+		if use amd64 && use multilib && [[ ${MERGE_TYPE} != "binary" ]] ; then
+			ebegin "Checking that IA32 emulation is enabled in the running kernel"
+			echo 'int main(){return 0;}' > "${T}/check-ia32-emulation.c"
+			local STAT
+			if ${CC-${CHOST}-gcc} ${CFLAGS_x86} "${T}/check-ia32-emulation.c" -o "${T}/check-ia32-emulation.elf32"; then
+				"${T}/check-ia32-emulation.elf32"
+				STAT=$?
+			else
+				# Don't fail here to allow single->multi ABI switch
+				# or recover from breakage like bug #646424
+				ewarn "Failed to compile the ABI test. Broken host glibc?"
+				STAT=0
+			fi
+			rm -f "${T}/check-ia32-emulation.elf32"
+			eend $STAT
+			[[ $STAT -eq 0 ]] || die "CONFIG_IA32_EMULATION must be enabled in the kernel to compile a multilib glibc."
+		fi
+
+	fi
+
+	# When we actually have to compile something...
+	if ! just_headers && [[ ${MERGE_TYPE} != "binary" ]] ; then
+		if [[ -d "${ESYSROOT}"/usr/lib/include ]] ; then
+			# bug #833620, bug #643302
+			eerror "Found ${ESYSROOT}/usr/lib/include directory!"
+			eerror "This is known to break glibc's build."
+			eerror "Please backup its contents then remove the directory."
+			die "Found directory (${ESYSROOT}/usr/lib/include) which will break build (bug #833620)!"
+		fi
+
+		if [[ ${CTARGET} == *-linux* ]] ; then
+			local run_kv build_kv want_kv
+
+			run_kv=$(g_get_running_KV)
+			build_kv=$(g_int_to_KV $(get_kheader_version))
+			want_kv=${MIN_KERN_VER}
+
+			if ! is_crosscompile && ! tc-is-cross-compiler ; then
+				# Building fails on an non-supporting kernel
+				ebegin "Checking running kernel version (${run_kv} >= ${want_kv})"
+				if ! eend_KV ${run_kv} ${want_kv} ; then
+					echo
+					eerror "You need a kernel of at least ${want_kv}!"
+					die "Kernel version too low!"
+				fi
+			fi
+
+			# Do not run this check for pkg_pretend, just pkg_setup and friends (if we ever get used there).
+			# It's plausible (seen it in the wild) that Portage will (correctly) schedule a linux-headers
+			# upgrade before glibc, but because pkg_pretend gets run before any packages are merged at all (not
+			# just glibc), the whole emerge gets aborted without a good reason. We probably don't
+			# need to run this check at all given we have a dependency on the right headers,
+			# but let's leave it as-is for now.
+			if [[ ${EBUILD_PHASE_FUNC} != pkg_pretend ]] ; then
+				ebegin "Checking linux-headers version (${build_kv} >= ${want_kv})"
+				if ! eend_KV ${build_kv} ${want_kv} ; then
+					echo
+					eerror "You need linux-headers of at least ${want_kv}!"
+					die "linux-headers version too low!"
+				fi
+			fi
+		fi
+	fi
+}
+
+upgrade_warning() {
+	is_crosscompile && return
+
+	if [[ ${MERGE_TYPE} != buildonly && -n ${REPLACING_VERSIONS} && -z ${ROOT} ]]; then
+		local oldv newv=$(ver_cut 1-2 ${PV})
+		for oldv in ${REPLACING_VERSIONS}; do
+			if ver_test ${oldv} -lt ${newv}; then
+				ewarn "After upgrading glibc, please restart all running processes."
+				ewarn "Be sure to include init (telinit u) or systemd (systemctl daemon-reexec)."
+				ewarn "Alternatively, reboot your system."
+				ewarn "(See bug #660556, bug #741116, bug #823756, etc)"
+				break
+			fi
+		done
+	fi
+}
+
+#
+# the phases
+#
+
+# pkg_pretend
+
+pkg_pretend() {
+	upgrade_warning
+}
+
+# pkg_setup
+
+pkg_setup() {
+	# see bug 682570
+	[[ -z ${BOOTSTRAP_RAP} ]] && python-any-r1_pkg_setup
+}
+
+# src_unpack
+
+src_unpack() {
+	setup_env
+
+	einfo "Checking general environment sanity."
+	sanity_prechecks
+
+	use multilib-bootstrap && unpack gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz
+
+	if [[ ${PV} == 9999* ]] ; then
+		EGIT_REPO_URI="https://anongit.gentoo.org/git/proj/toolchain/glibc-patches.git"
+		EGIT_CHECKOUT_DIR=${WORKDIR}/patches-git
+		git-r3_src_unpack
+		mv patches-git/9999 patches || die
+
+		EGIT_REPO_URI="https://sourceware.org/git/glibc.git"
+		EGIT_CHECKOUT_DIR=${S}
+		git-r3_src_unpack
+	else
+		unpack ${P}.tar.xz
+
+		cd "${WORKDIR}" || die
+		unpack glibc-${PV}-patches-${PATCH_VER}.tar.xz
+	fi
+
+	cd "${WORKDIR}" || die
+	use systemd && unpack glibc-systemd-${GLIBC_SYSTEMD_VER}.tar.gz
+}
+
+# src_prepare
+
+src_prepare() {
+	local patchsetname
+	if ! use vanilla ; then
+		if [[ ${PV} == 9999* ]] ; then
+			patchsetname="from git master"
+		else
+			patchsetname="${PV}-${PATCH_VER}"
+		fi
+		einfo "Applying Gentoo Glibc patchset ${patchsetname}"
+		eapply "${WORKDIR}"/patches
+		einfo "Done."
+	fi
+
+	default
+
+	gnuconfig_update
+
+	cd "${WORKDIR}" || die
+	find . -name configure -exec touch {} +
+
+	# Fix permissions on some of the scripts.
+	chmod u+x "${S}"/scripts/*.sh
+
+	cd "${S}" || die
+}
+
+# src_configure
+
+glibc_do_configure() {
+	dump_build_environment
+
+	local myconf=()
+
+	# Use '=strong' instead of '=all' to protect only functions
+	# worth protecting from stack smashes.
+	myconf+=( --enable-stack-protector=$(usex ssp strong no) )
+
+	# Keep a whitelist of targets supporing IFUNC. glibc's ./configure
+	# is not robust enough to detect proper support:
+	#    https://bugs.gentoo.org/641216
+	#    https://sourceware.org/PR22634#c0
+	case $(tc-arch ${CTARGET}) in
+		# Keep whitelist of targets where autodetection mostly works.
+		amd64|x86|sparc|ppc|ppc64|arm|arm64|s390|riscv|loong) ;;
+		# Blacklist everywhere else
+		*) myconf+=( libc_cv_ld_gnu_indirect_function=no ) ;;
+	esac
+
+	# Enable Intel Control-flow Enforcement Technology on amd64 if requested
+	case ${CTARGET} in
+		x86_64-*) myconf+=( $(use_enable cet) ) ;;
+		*) ;;
+	esac
+
+	[[ $(tc-is-softfloat) == "yes" ]] && myconf+=( --without-fp )
+
+	myconf+=( --enable-kernel=${MIN_KERN_VER} )
+
+	# Since SELinux support is only required for nscd, only enable it if:
+	# 1. USE selinux
+	# 2. only for the primary ABI on multilib systems
+	# 3. Not a crosscompile
+	if ! is_crosscompile && use selinux ; then
+		if use multilib ; then
+			if is_final_abi ; then
+				myconf+=( --with-selinux )
+			else
+				myconf+=( --without-selinux )
+			fi
+		else
+			myconf+=( --with-selinux )
+		fi
+	else
+		myconf+=( --without-selinux )
+	fi
+
+	# Force a few tests where we always know the answer but
+	# configure is incapable of finding it.
+	if is_crosscompile ; then
+		export \
+			libc_cv_c_cleanup=yes \
+			libc_cv_forced_unwind=yes
+	fi
+
+	myconf+=(
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		$(use_enable profile)
+		$(use_with gd)
+		--with-headers=$(build_eprefix)$(alt_build_headers)
+		--prefix="$(host_eprefix)/usr"
+		--sysconfdir="$(host_eprefix)/etc"
+		--localstatedir="$(host_eprefix)/var"
+		--libdir='$(prefix)'/$(get_libdir)
+		--mandir='$(prefix)'/share/man
+		--infodir='$(prefix)'/share/info
+		--libexecdir='$(libdir)'/misc/glibc
+		--with-bugurl=https://bugs.gentoo.org/
+		--with-pkgversion="$(glibc_banner)"
+		$(use_enable crypt)
+		$(use_multiarch || echo --disable-multi-arch)
+		$(use_enable systemtap)
+		$(use_enable nscd)
+
+		# /usr/bin/mtrace has a Perl shebang. Gentoo Prefix QA checks fail if
+		# Perl hasn't been installed inside the prefix yet and configure picks
+		# up a Perl from outside the prefix instead. configure will fail to
+		# execute Perl during configure if we're cross-compiling a prefix, but
+		# it will just disable mtrace in that case.
+		# Note: mtrace is needed by the test suite.
+		ac_cv_path_PERL="$(usex perl "${EPREFIX}"/usr/bin/perl $(usex test "${EPREFIX}"/usr/bin/perl $(usex doc "${EPREFIX}"/usr/bin/perl no)))"
+
+		# locale data is arch-independent
+		# https://bugs.gentoo.org/753740
+		libc_cv_complocaledir='${exec_prefix}/lib/locale'
+
+		# -march= option tricks build system to infer too
+		# high ISA level: https://sourceware.org/PR27318
+		libc_cv_include_x86_isa_level=no
+
+		# Explicit override of https://sourceware.org/PR27991
+		# exposes a bug in glibc's configure:
+		# https://sourceware.org/PR27991
+		libc_cv_have_x86_lahf_sahf=no
+		libc_cv_have_x86_movbe=no
+
+		${EXTRA_ECONF}
+	)
+
+	# We rely on sys-libs/timezone-data for timezone tools normally.
+	myconf+=( $(use_enable vanilla timezone-tools) )
+
+	# These libs don't have configure flags.
+	ac_cv_lib_audit_audit_log_user_avc_message=$(usex audit || echo no)
+	ac_cv_lib_cap_cap_init=$(usex caps || echo no)
+
+	# There is no configure option for this and we need to export it
+	# since the glibc build will re-run configure on itself
+	export libc_cv_rootsbindir="$(host_eprefix)/sbin"
+	export libc_cv_slibdir="$(host_eprefix)/$(get_libdir)"
+
+	local builddir=$(builddir nptl)
+	mkdir -p "${builddir}"
+	cd "${builddir}"
+	set -- "${S}"/configure "${myconf[@]}"
+	echo "$@"
+	"$@" || die "failed to configure glibc"
+
+	# ia64 static cross-compilers are a pita in so much that they
+	# can't produce static ELFs (as the libgcc.a is broken).  so
+	# disable building of the programs for those targets if it
+	# doesn't work.
+	# XXX: We could turn this into a compiler test, but ia64 is
+	# the only one that matters, so this should be fine for now.
+	if is_crosscompile && [[ ${CTARGET} == ia64* ]] ; then
+		sed -i '1i+link-static = touch $@' config.make
+	fi
+
+	# If we're trying to migrate between ABI sets, we need
+	# to lie and use a local copy of gcc.  Like if the system
+	# is built with MULTILIB_ABIS="amd64 x86" but we want to
+	# add x32 to it, gcc/glibc don't yet support x32.
+	#
+	if [[ -n ${GCC_BOOTSTRAP_VER} ]] && use multilib-bootstrap ; then
+		echo 'main(){}' > "${T}"/test.c
+		if ! $(tc-getCC ${CTARGET}) ${CFLAGS} ${LDFLAGS} "${T}"/test.c -Wl,-emain -lgcc 2>/dev/null ; then
+			sed -i -e '/^CC = /s:$: -B$(objdir)/../'"gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}/${ABI}:" config.make || die
+		fi
+	fi
+}
+
+glibc_headers_configure() {
+	export ABI=default
+
+	local builddir=$(builddir "headers")
+	mkdir -p "${builddir}"
+	cd "${builddir}"
+
+	# if we don't have a compiler yet, we can't really test it now ...
+	# hopefully they don't affect header generation, so let's hope for
+	# the best here ...
+	local v vars=(
+		ac_cv_header_cpuid_h=yes
+		libc_cv_{386,390,alpha,arm,hppa,ia64,mips,{powerpc,sparc}{,32,64},sh,x86_64}_tls=yes
+		libc_cv_asm_cfi_directives=yes
+		libc_cv_broken_visibility_attribute=no
+		libc_cv_c_cleanup=yes
+		libc_cv_compiler_powerpc64le_binary128_ok=yes
+		libc_cv_forced_unwind=yes
+		libc_cv_gcc___thread=yes
+		libc_cv_mlong_double_128=yes
+		libc_cv_mlong_double_128ibm=yes
+		libc_cv_ppc_machine=yes
+		libc_cv_ppc_rel16=yes
+		libc_cv_predef_fortify_source=no
+		libc_cv_target_power8_ok=yes
+		libc_cv_visibility_attribute=yes
+		libc_cv_z_combreloc=yes
+		libc_cv_z_execstack=yes
+		libc_cv_z_initfirst=yes
+		libc_cv_z_nodelete=yes
+		libc_cv_z_nodlopen=yes
+		libc_cv_z_relro=yes
+		libc_mips_abi=${ABI}
+		libc_mips_float=$([[ $(tc-is-softfloat) == "yes" ]] && echo soft || echo hard)
+		# These libs don't have configure flags.
+		ac_cv_lib_audit_audit_log_user_avc_message=no
+		ac_cv_lib_cap_cap_init=no
+	)
+
+	einfo "Forcing cached settings:"
+	for v in "${vars[@]}" ; do
+		einfo " ${v}"
+		export ${v}
+	done
+
+	local headers_only_arch_CPPFLAGS=()
+
+	# Blow away some random CC settings that screw things up. #550192
+	if [[ -d ${S}/sysdeps/mips ]]; then
+		pushd "${S}"/sysdeps/mips >/dev/null
+		sed -i -e '/^CC +=/s:=.*:= -D_MIPS_SZPTR=32:' mips32/Makefile mips64/n32/Makefile || die
+		sed -i -e '/^CC +=/s:=.*:= -D_MIPS_SZPTR=64:' mips64/n64/Makefile || die
+
+		# Force the mips ABI to the default.  This is OK because the set of
+		# installed headers in this phase is the same between the 3 ABIs.
+		# If this ever changes, this hack will break, but that's unlikely
+		# as glibc discourages that behavior.
+		# https://crbug.com/647033
+		sed -i -e 's:abiflag=.*:abiflag=_ABIO32:' preconfigure || die
+
+		popd >/dev/null
+	fi
+
+	case ${CTARGET} in
+	riscv*)
+		# RISC-V interrogates the compiler to determine which target to
+		# build.  If building the headers then we don't strictly need a
+		# RISC-V compiler, so the built-in definitions that are provided
+		# along with all RISC-V compiler might not exist.  This causes
+		# glibc's RISC-V preconfigure script to blow up.  Since we're just
+		# building the headers any value will actually work here, so just
+		# pick the standard one (rv64g/lp64d) to make the build scripts
+		# happy for now -- the headers are all the same anyway so it
+		# doesn't matter.
+		headers_only_arch_CPPFLAGS+=(
+			-D__riscv_xlen=64
+			-D__riscv_flen=64
+			-D__riscv_float_abi_double=1
+			-D__riscv_atomic=1
+		) ;;
+	esac
+
+	local myconf=()
+	myconf+=(
+		--disable-sanity-checks
+		--enable-hacker-mode
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		--with-headers=$(build_eprefix)$(alt_build_headers)
+		--prefix="$(host_eprefix)/usr"
+		$(use_enable crypt)
+		${EXTRA_ECONF}
+	)
+
+	# Nothing is compiled here which would affect the headers for the target.
+	# So forcing CC/CFLAGS is sane.
+	local headers_only_CC=$(tc-getBUILD_CC)
+	local headers_only_CFLAGS="-O1 -pipe"
+	local headers_only_CPPFLAGS="-U_FORTIFY_SOURCE ${headers_only_arch_CPPFLAGS[*]}"
+	local headers_only_LDFLAGS=""
+	set -- "${S}"/configure "${myconf[@]}"
+	echo \
+		"CC=${headers_only_CC}" \
+		"CFLAGS=${headers_only_CFLAGS}" \
+		"CPPFLAGS=${headers_only_CPPFLAGS}" \
+		"LDFLAGS=${headers_only_LDFLAGS}" \
+		"$@"
+	CC=${headers_only_CC} \
+	CFLAGS=${headers_only_CFLAGS} \
+	CPPFLAGS=${headers_only_CPPFLAGS} \
+	LDFLAGS="" \
+	"$@" || die "failed to configure glibc"
+}
+
+do_src_configure() {
+	if just_headers ; then
+		glibc_headers_configure
+	else
+		glibc_do_configure nptl
+	fi
+}
+
+src_configure() {
+	foreach_abi do_src_configure
+}
+
+# src_compile
+
+do_src_compile() {
+	emake -C "$(builddir nptl)"
+}
+
+src_compile() {
+	if just_headers ; then
+		return
+	fi
+
+	foreach_abi do_src_compile
+}
+
+# src_test
+
+glibc_src_test() {
+	cd "$(builddir nptl)"
+
+	local myxfailparams=""
+	if [[ "${GENTOO_GLIBC_XFAIL_TESTS}" == "yes" ]] ; then
+		local virt=$(systemd-detect-virt 2>/dev/null)
+		if [[ ${virt} == systemd-nspawn ]] ; then
+			ewarn "Skipping extra tests because in systemd-nspawn container"
+			XFAIL_TEST_LIST+=( "${XFAIL_NSPAWN_TEST_LIST[@]}" )
+		fi
+
+		for myt in ${XFAIL_TEST_LIST[@]} ; do
+			myxfailparams+="test-xfail-${myt}=yes "
+		done
+	fi
+
+	# sandbox does not understand unshare() and prevents
+	# writes to /proc/, which makes many tests fail
+
+	# we give the tests a bit more time to avoid spurious
+	# bug reports on slow arches
+
+	SANDBOX_ON=0 LD_PRELOAD= TIMEOUTFACTOR=16 emake ${myxfailparams} check
+}
+
+src_test() {
+	if just_headers ; then
+		return
+	fi
+
+	foreach_abi glibc_src_test || die "tests failed"
+}
+
+# src_install
+
+run_locale_gen() {
+	# if the host locales.gen contains no entries, we'll install everything
+	local root="$1"
+	local inplace=""
+
+	if [[ "${root}" == "--inplace-glibc" ]] ; then
+		inplace="--inplace-glibc"
+		root="$2"
+	fi
+
+	local locale_list="${root%/}/etc/locale.gen"
+
+	pushd "${ED}"/$(get_libdir) >/dev/null
+
+	if [[ -z $(locale-gen --list --config "${locale_list}") ]] ; then
+		[[ -z ${inplace} ]] && ewarn "Generating all locales; edit /etc/locale.gen to save time/space"
+		locale_list="${root%/}/usr/share/i18n/SUPPORTED"
+	fi
+
+	# bug 736794: we need to be careful with the parallelization... the number of
+	# processors saved in the environment of a binary package may differ strongly
+	# from the number of processes available during postinst
+	local mygenjobs="$(makeopts_jobs)"
+	if [[ "${EMERGE_FROM}" == "binary" ]] ; then
+		mygenjobs="$(nproc)"
+	fi
+
+	set -- locale-gen ${inplace} --jobs "${mygenjobs}" --config "${locale_list}" \
+		--destdir "${root}"
+	echo "$@"
+	"$@"
+
+	popd >/dev/null
+}
+
+glibc_do_src_install() {
+	local builddir=$(builddir nptl)
+	cd "${builddir}"
+
+	emake install_root="${D}/$(build_eprefix)$(alt_prefix)" install
+
+	# This version (2.26) provides some compatibility libraries for the NIS/NIS+ support
+	# which come without headers etc. Only needed for binary packages since the
+	# external net-libs/libnsl has increased soversion. Keep only versioned libraries.
+	find "${D}" -name "libnsl.a" -delete
+	find "${D}" -name "libnsl.so" -delete
+
+	# Normally upstream_pv is ${PV}. Live ebuilds are exception, there we need
+	# to infer upstream version:
+	# '#define VERSION "2.26.90"' -> '2.26.90'
+	local upstream_pv=$(sed -n -r 's/#define VERSION "(.*)"/\1/p' "${S}"/version.h)
+
+	# Avoid stripping binaries not targeted by ${CHOST}. Or else
+	# ${CHOST}-strip would break binaries build for ${CTARGET}.
+	is_crosscompile && dostrip -x /
+
+	# gdb thread introspection relies on local libpthreads symbols. stripping breaks it
+	# See Note [Disable automatic stripping]
+	dostrip -x $(alt_libdir)/libpthread-${upstream_pv}.so
+	# valgrind requires knowledge about ld.so symbols.
+	dostrip -x $(alt_libdir)/ld-*.so*
+
+	if [[ -e ${ED}/$(alt_usrlibdir)/libm-${upstream_pv}.a ]] ; then
+		# Move versioned .a file out of libdir to evade portage QA checks
+		# instead of using gen_usr_ldscript(). We fix ldscript as:
+		# "GROUP ( /usr/lib64/libm-<pv>.a ..." -> "GROUP ( /usr/lib64/glibc-<pv>/libm-<pv>.a ..."
+		sed -i "s@\(libm-${upstream_pv}.a\)@${P}/\1@" "${ED}"/$(alt_usrlibdir)/libm.a || die
+		dodir $(alt_usrlibdir)/${P}
+		mv "${ED}"/$(alt_usrlibdir)/libm-${upstream_pv}.a "${ED}"/$(alt_usrlibdir)/${P}/libm-${upstream_pv}.a || die
+	fi
+
+	# We configure toolchains for standalone prefix systems with a sysroot,
+	# which is prepended to paths in ld scripts, so strip the prefix from these.
+	# Before: GROUP ( /foo/lib64/libc.so.6 /foo/usr/lib64/libc_nonshared.a  AS_NEEDED ( /foo/lib64/ld-linux-x86-64.so.2 ) )
+	# After: GROUP ( /lib64/libc.so.6 /usr/lib64/libc_nonshared.a  AS_NEEDED ( /lib64/ld-linux-x86-64.so.2 ) )
+	if [[ -n $(host_eprefix) ]] ; then
+		local file
+		grep -lZIF "ld script" "${ED}/$(alt_usrlibdir)"/lib*.{a,so} 2>/dev/null | while read -rd '' file ; do
+			sed -i "s|$(host_eprefix)/|/|g" "${file}" || die
+		done
+	fi
+
+	# We'll take care of the cache ourselves
+	rm -f "${ED}"/etc/ld.so.cache
+
+	# Everything past this point just needs to be done once ...
+	is_final_abi || return 0
+
+	# Make sure the non-native interp can be found on multilib systems even
+	# if the main library set isn't installed into the right place.  Maybe
+	# we should query the active gcc for info instead of hardcoding it ?
+	local i ldso_abi ldso_name
+	local ldso_abi_list=(
+		# x86
+		amd64   /lib64/ld-linux-x86-64.so.2
+		x32     /libx32/ld-linux-x32.so.2
+		x86     /lib/ld-linux.so.2
+		# mips
+		o32     /lib/ld.so.1
+		n32     /lib32/ld.so.1
+		n64     /lib64/ld.so.1
+		# powerpc
+		ppc     /lib/ld.so.1
+		# riscv
+		ilp32d  /lib/ld-linux-riscv32-ilp32d.so.1
+		ilp32   /lib/ld-linux-riscv32-ilp32.so.1
+		lp64d   /lib/ld-linux-riscv64-lp64d.so.1
+		lp64    /lib/ld-linux-riscv64-lp64.so.1
+		# s390
+		s390    /lib/ld.so.1
+		s390x   /lib/ld64.so.1
+		# sparc
+		sparc32 /lib/ld-linux.so.2
+		sparc64 /lib64/ld-linux.so.2
+	)
+	case $(tc-endian) in
+	little)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64.so.1
+			# ELFv2 (glibc does not support ELFv1 on LE)
+			ppc64   /lib64/ld64.so.2
+		)
+		;;
+	big)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64_be.so.1
+			# ELFv1 (glibc does not support ELFv2 on BE)
+			ppc64   /lib64/ld64.so.1
+		)
+		;;
+	esac
+	if [[ ${SYMLINK_LIB} == "yes" ]] && [[ ! -e ${ED}/$(alt_prefix)/lib ]] ; then
+		dosym $(get_abi_LIBDIR ${DEFAULT_ABI}) $(alt_prefix)/lib
+	fi
+	for (( i = 0; i < ${#ldso_abi_list[@]}; i += 2 )) ; do
+		ldso_abi=${ldso_abi_list[i]}
+		has ${ldso_abi} $(get_install_abis) || continue
+
+		ldso_name="$(alt_prefix)${ldso_abi_list[i+1]}"
+		if [[ ! -L ${ED}/${ldso_name} && ! -e ${ED}/${ldso_name} ]] ; then
+			dosym ../$(get_abi_LIBDIR ${ldso_abi})/${ldso_name##*/} ${ldso_name}
+		fi
+	done
+
+	# In the LSB 5.0 definition, someone had the excellent idea to "standardize"
+	# the runtime loader name, see also https://xkcd.com/927/
+	# Normally, in Gentoo one should never come across executables that require this.
+	# However, binary commercial packages are known to adhere to weird practices.
+	# https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-AMD64/LSB-Core-AMD64.html#BASELIB
+	local lsb_ldso_name native_ldso_name lsb_ldso_abi
+	local lsb_ldso_abi_list=(
+		# x86
+		amd64	ld-linux-x86-64.so.2	ld-lsb-x86-64.so.3
+	)
+	for (( i = 0; i < ${#lsb_ldso_abi_list[@]}; i += 3 )) ; do
+		lsb_ldso_abi=${lsb_ldso_abi_list[i]}
+		native_ldso_name=${lsb_ldso_abi_list[i+1]}
+		lsb_ldso_name=${lsb_ldso_abi_list[i+2]}
+		has ${lsb_ldso_abi} $(get_install_abis) || continue
+
+		if [[ ! -L ${ED}/$(get_abi_LIBDIR ${lsb_ldso_abi})/${lsb_ldso_name} && ! -e ${ED}/$(get_abi_LIBDIR ${lsb_ldso_abi})/${lsb_ldso_name} ]] ; then
+			dosym ${native_ldso_name} "$(alt_prefix)/$(get_abi_LIBDIR ${lsb_ldso_abi})/${lsb_ldso_name}"
+		fi
+	done
+
+	# With devpts under Linux mounted properly, we do not need the pt_chown
+	# binary to be setuid.  This is because the default owners/perms will be
+	# exactly what we want.
+	if ! use suid ; then
+		find "${ED}" -name pt_chown -exec chmod -s {} +
+	fi
+
+	#################################################################
+	# EVERYTHING AFTER THIS POINT IS FOR NATIVE GLIBC INSTALLS ONLY #
+	#################################################################
+
+	# Make sure we install some symlink hacks so that when we build
+	# a 2nd stage cross-compiler, gcc finds the target system
+	# headers correctly.  See gcc/doc/gccinstall.info
+	if is_crosscompile ; then
+		# We need to make sure that /lib and /usr/lib always exists.
+		# gcc likes to use relative paths to get to its multilibs like
+		# /usr/lib/../lib64/.  So while we don't install any files into
+		# /usr/lib/, we do need it to exist.
+		keepdir $(alt_prefix)/lib
+		keepdir $(alt_prefix)/usr/lib
+
+		dosym usr/include $(alt_prefix)/sys-include
+		return 0
+	fi
+
+	# Files for Debian-style locale updating
+	dodir /usr/share/i18n
+	sed \
+		-e "/^#/d" \
+		-e "/SUPPORTED-LOCALES=/d" \
+		-e "s: \\\\::g" -e "s:/: :g" \
+		"${S}"/localedata/SUPPORTED > "${ED}"/usr/share/i18n/SUPPORTED \
+		|| die "generating /usr/share/i18n/SUPPORTED failed"
+
+	cd "${S}" || die
+
+	# Install misc network config files
+	insinto /etc
+	doins posix/gai.conf
+
+	if use systemd ; then
+		doins "${WORKDIR}/glibc-systemd-${GLIBC_SYSTEMD_VER}/gentoo-config/nsswitch.conf"
+	else
+		doins nss/nsswitch.conf
+	fi
+
+	# Gentoo-specific
+	newins "${FILESDIR}"/host.conf-1 host.conf
+
+	if use nscd ; then
+		doins nscd/nscd.conf
+
+		newinitd "$(prefixify_ro "${FILESDIR}"/nscd-1)" nscd
+
+		local nscd_args=(
+			-e "s:@PIDFILE@:$(strings "${ED}"/usr/sbin/nscd | grep nscd.pid):"
+		)
+
+		sed -i "${nscd_args[@]}" "${ED}"/etc/init.d/nscd
+
+		use systemd && systemd_dounit nscd/nscd.service
+		newtmpfiles nscd/nscd.tmpfiles nscd.conf
+	fi
+
+	echo 'LDPATH="include ld.so.conf.d/*.conf"' > "${T}"/00glibc
+	doenvd "${T}"/00glibc
+
+	for d in BUGS ChangeLog CONFORMANCE FAQ NEWS NOTES PROJECTS README* ; do
+		[[ -s ${d} ]] && dodoc ${d}
+	done
+	dodoc -r ChangeLog.old
+
+	# Prevent overwriting of the /etc/localtime symlink.  We'll handle the
+	# creation of the "factory" symlink in pkg_postinst().
+	rm -f "${ED}"/etc/localtime
+
+	# Generate all locales if this is a native build as locale generation
+	if use compile-locales && ! is_crosscompile ; then
+		run_locale_gen --inplace-glibc "${ED}/"
+	fi
+}
+
+glibc_headers_install() {
+	local builddir=$(builddir "headers")
+	cd "${builddir}"
+	emake install_root="${D}/$(build_eprefix)$(alt_prefix)" install-headers
+
+	insinto $(alt_headers)/gnu
+	doins "${S}"/include/gnu/stubs.h
+
+	# Make sure we install the sys-include symlink so that when
+	# we build a 2nd stage cross-compiler, gcc finds the target
+	# system headers correctly.  See gcc/doc/gccinstall.info
+	dosym usr/include $(alt_prefix)/sys-include
+}
+
+src_install() {
+	if just_headers ; then
+		export ABI=default
+		glibc_headers_install
+		return
+	fi
+
+	foreach_abi glibc_do_src_install
+
+	if ! use static-libs ; then
+		einfo "Not installing static glibc libraries"
+		find "${ED}" -name "*.a" -and -not -name "*_nonshared.a" -delete
+	fi
+}
+
+# Simple test to make sure our new glibc isn't completely broken.
+# Make sure we don't test with statically built binaries since
+# they will fail.  Also, skip if this glibc is a cross compiler.
+#
+# If coreutils is built with USE=multicall, some of these files
+# will just be wrapper scripts, not actual ELFs we can test.
+glibc_sanity_check() {
+	cd / #228809
+
+	# We enter ${ED} so to avoid trouble if the path contains
+	# special characters; for instance if the path contains the
+	# colon character (:), then the linker will try to split it
+	# and look for the libraries in an unexpected place. This can
+	# lead to unsafe code execution if the generated prefix is
+	# within a world-writable directory.
+	# (e.g. /var/tmp/portage:${HOSTNAME})
+	pushd "${ED}"/$(get_libdir) >/dev/null
+
+	# first let's find the actual dynamic linker here
+	# symlinks may point to the wrong abi
+	local newldso=$(find . -maxdepth 1 -name 'ld*so.?' -type f -print -quit)
+
+	einfo Last-minute run tests with ${newldso} in /$(get_libdir) ...
+
+	local x striptest
+	for x in cal date env free ls true uname uptime ; do
+		x=$(type -p ${x})
+		[[ -z ${x} || ${x} != ${EPREFIX}/* ]] && continue
+		striptest=$(LC_ALL="C" file -L ${x} 2>/dev/null) || continue
+		case ${striptest} in
+		*"statically linked"*) continue;;
+		*"ASCII text"*) continue;;
+		esac
+		# We need to clear the locale settings as the upgrade might want
+		# incompatible locale data.  This test is not for verifying that.
+		LC_ALL=C \
+		${newldso} --library-path . ${x} > /dev/null \
+			|| die "simple run test (${x}) failed"
+	done
+
+	popd >/dev/null
+}
+
+pkg_preinst() {
+	# nothing to do if just installing headers
+	just_headers && return
+
+	einfo "Checking general environment sanity."
+	sanity_prechecks
+
+	# prepare /etc/ld.so.conf.d/ for files
+	mkdir -p "${EROOT}"/etc/ld.so.conf.d
+
+	# Default /etc/hosts.conf:multi to on for systems with small dbs.
+	if [[ $(wc -l < "${EROOT}"/etc/hosts) -lt 1000 ]] ; then
+		sed -i '/^multi off/s:off:on:' "${ED}"/etc/host.conf
+		einfo "Defaulting /etc/host.conf:multi to on"
+	fi
+
+	[[ -n ${ROOT} ]] && return 0
+	[[ -d ${ED}/$(get_libdir) ]] || return 0
+	[[ -z ${BOOTSTRAP_RAP} ]] && glibc_sanity_check
+
+	if [[ -L ${EROOT}/usr/lib/locale ]]; then
+		# Help portage migrate this to a directory
+		# https://bugs.gentoo.org/753740
+		rm "${EROOT}"/usr/lib/locale || die
+	fi
+
+	# Keep around libcrypt so that Perl doesn't break when merging libxcrypt
+	# (libxcrypt is the new provider for now of libcrypt.so.{1,2}).
+	# bug #802207
+	if ! use crypt && has_version "${CATEGORY}/${PN}[crypt]" && ! has preserve-libs ${FEATURES}; then
+		PRESERVED_OLD_LIBCRYPT=1
+		cp -p "${EROOT}/$(get_libdir)/libcrypt$(get_libname 1)" "${T}/libcrypt$(get_libname 1)" || die
+	else
+		PRESERVED_OLD_LIBCRYPT=0
+	fi
+}
+
+pkg_postinst() {
+	# nothing to do if just installing headers
+	just_headers && return
+
+	if ! tc-is-cross-compiler && [[ -x ${EROOT}/usr/sbin/iconvconfig ]] ; then
+		# Generate fastloading iconv module configuration file.
+		"${EROOT}"/usr/sbin/iconvconfig --prefix="${ROOT}/"
+	fi
+
+	if ! is_crosscompile && [[ -z ${ROOT} ]] ; then
+		use compile-locales || run_locale_gen "${EROOT}/"
+	fi
+
+	upgrade_warning
+
+	# Check for sanity of /etc/nsswitch.conf, take 2
+	if [[ -e ${EROOT}/etc/nsswitch.conf ]] && ! has_version sys-auth/libnss-nis ; then
+		local entry
+		for entry in passwd group shadow; do
+			if grep -E -q "^[ \t]*${entry}:.*nis" "${EROOT}"/etc/nsswitch.conf; then
+				ewarn ""
+				ewarn "Your ${EROOT}/etc/nsswitch.conf uses NIS. Support for that has been"
+				ewarn "removed from glibc and is now provided by the package"
+				ewarn "  sys-auth/libnss-nis"
+				ewarn "Install it now to keep your NIS setup working."
+				ewarn ""
+			fi
+		done
+	fi
+
+	if [[ ${PRESERVED_OLD_LIBCRYPT} -eq 1 ]] ; then
+		cp -p "${T}/libcrypt$(get_libname 1)" "${EROOT}/$(get_libdir)/libcrypt$(get_libname 1)" || die
+		preserve_old_lib_notify /$(get_libdir)/libcrypt$(get_libname 1)
+
+		elog "Please ignore a possible later error message about a file collision involving"
+		elog "${EROOT}/$(get_libdir)/libcrypt$(get_libname 1). We need to preserve this file for the moment to keep"
+		elog "the upgrade working, but it also needs to be overwritten when"
+		elog "sys-libs/libxcrypt is installed. See bug 802210 for more details."
+	fi
+}
diff --git a/sys-libs/glibc/glibc-2.38-r9.ebuild b/sys-libs/glibc/glibc-2.38-r9.ebuild
new file mode 100644
index 000000000000..2327ebd84994
--- /dev/null
+++ b/sys-libs/glibc/glibc-2.38-r9.ebuild
@@ -0,0 +1,1718 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+# Bumping notes: https://wiki.gentoo.org/wiki/Project:Toolchain/sys-libs/glibc
+# Please read & adapt the page as necessary if obsolete.
+
+PYTHON_COMPAT=( python3_{9..12} )
+TMPFILES_OPTIONAL=1
+
+inherit python-any-r1 prefix preserve-libs toolchain-funcs flag-o-matic gnuconfig \
+	multilib systemd multiprocessing tmpfiles
+
+DESCRIPTION="GNU libc C library"
+HOMEPAGE="https://www.gnu.org/software/libc/"
+LICENSE="LGPL-2.1+ BSD HPND ISC inner-net rc PCRE"
+SLOT="2.2"
+
+EMULTILIB_PKG="true"
+
+# Gentoo patchset (ignored for live ebuilds)
+PATCH_VER=9
+PATCH_DEV=dilfridge
+
+# gcc mulitilib bootstrap files version
+GCC_BOOTSTRAP_VER=20201208
+
+# systemd integration version
+GLIBC_SYSTEMD_VER=20210729
+
+# Minimum kernel version that glibc requires
+MIN_KERN_VER="3.2.0"
+
+# Minimum pax-utils version needed (which contains any new syscall changes for
+# its seccomp filter!). Please double check this!
+MIN_PAX_UTILS_VER="1.3.3"
+
+if [[ ${PV} == 9999* ]]; then
+	inherit git-r3
+else
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86"
+	SRC_URI="mirror://gnu/glibc/${P}.tar.xz"
+	SRC_URI+=" https://dev.gentoo.org/~${PATCH_DEV}/distfiles/${P}-patches-${PATCH_VER}.tar.xz"
+fi
+
+SRC_URI+=" multilib-bootstrap? ( https://dev.gentoo.org/~dilfridge/distfiles/gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz )"
+SRC_URI+=" systemd? ( https://gitweb.gentoo.org/proj/toolchain/glibc-systemd.git/snapshot/glibc-systemd-${GLIBC_SYSTEMD_VER}.tar.gz )"
+
+IUSE="audit caps cet compile-locales +crypt custom-cflags doc gd hash-sysv-compat headers-only +multiarch multilib multilib-bootstrap nscd perl profile selinux +ssp stack-realign +static-libs suid systemd systemtap test vanilla"
+
+# Here's how the cross-compile logic breaks down ...
+#  CTARGET - machine that will target the binaries
+#  CHOST   - machine that will host the binaries
+#  CBUILD  - machine that will build the binaries
+# If CTARGET != CHOST, it means you want a libc for cross-compiling.
+# If CHOST != CBUILD, it means you want to cross-compile the libc.
+#  CBUILD = CHOST = CTARGET    - native build/install
+#  CBUILD != (CHOST = CTARGET) - cross-compile a native build
+#  (CBUILD = CHOST) != CTARGET - libc for cross-compiler
+#  CBUILD != CHOST != CTARGET  - cross-compile a libc for a cross-compiler
+# For install paths:
+#  CHOST = CTARGET  - install into /
+#  CHOST != CTARGET - install into /usr/CTARGET/
+#
+export CBUILD=${CBUILD:-${CHOST}}
+export CTARGET=${CTARGET:-${CHOST}}
+if [[ ${CTARGET} == ${CHOST} ]] ; then
+	if [[ ${CATEGORY} == cross-* ]] ; then
+		export CTARGET=${CATEGORY#cross-}
+	fi
+fi
+
+# Note [Disable automatic stripping]
+# Disabling automatic stripping for a few reasons:
+# - portage's attempt to strip breaks non-native binaries at least on
+#   arm: bug #697428
+# - portage's attempt to strip libpthread.so.0 breaks gdb thread
+#   enumeration: bug #697910. This is quite subtle:
+#   * gdb uses glibc's libthread_db-1.0.so to enumerate threads.
+#   * libthread_db-1.0.so needs access to libpthread.so.0 local symbols
+#     via 'ps_pglobal_lookup' symbol defined in gdb.
+#   * 'ps_pglobal_lookup' uses '.symtab' section table to resolve all
+#     known symbols in 'libpthread.so.0'. Specifically 'nptl_version'
+#     (unexported) is used to sanity check compatibility before enabling
+#     debugging.
+#     Also see https://sourceware.org/gdb/wiki/FAQ#GDB_does_not_see_any_threads_besides_the_one_in_which_crash_occurred.3B_or_SIGTRAP_kills_my_program_when_I_set_a_breakpoint
+#   * normal 'strip' command trims '.symtab'
+#   Thus our main goal here is to prevent 'libpthread.so.0' from
+#   losing it's '.symtab' entries.
+# - similarly, valgrind requires knowledge about symbols in ld.so:
+#	bug #920753
+# As Gentoo's strip does not allow us to pass less aggressive stripping
+# options and does not check the machine target we strip selectively.
+
+# We need a new-enough binutils/gcc to match upstream baseline.
+# Also we need to make sure our binutils/gcc supports TLS,
+# and that gcc already contains the hardened patches.
+# Lastly, let's avoid some openssh nastiness, bug 708224, as
+# convenience to our users.
+
+IDEPEND="
+	!compile-locales? ( sys-apps/locale-gen )
+"
+BDEPEND="
+	${PYTHON_DEPS}
+	>=app-misc/pax-utils-${MIN_PAX_UTILS_VER}
+	sys-devel/bison
+	compile-locales? ( sys-apps/locale-gen )
+	doc? (
+		dev-lang/perl
+		sys-apps/texinfo
+	)
+	test? (
+		dev-lang/perl
+		>=net-dns/libidn2-2.3.0
+	)
+"
+COMMON_DEPEND="
+	gd? ( media-libs/gd:2= )
+	nscd? ( selinux? (
+		audit? ( sys-process/audit )
+		caps? ( sys-libs/libcap )
+	) )
+	suid? ( caps? ( sys-libs/libcap ) )
+	selinux? ( sys-libs/libselinux )
+	systemtap? ( dev-util/systemtap )
+"
+DEPEND="${COMMON_DEPEND}
+"
+RDEPEND="${COMMON_DEPEND}
+	!<app-misc/pax-utils-${MIN_PAX_UTILS_VER}
+	perl? ( dev-lang/perl )
+"
+
+RESTRICT="!test? ( test )"
+
+if [[ ${CATEGORY} == cross-* ]] ; then
+	BDEPEND+=" !headers-only? (
+		>=${CATEGORY}/binutils-2.27
+		>=${CATEGORY}/gcc-6.2
+	)"
+	[[ ${CATEGORY} == *-linux* ]] && DEPEND+=" ${CATEGORY}/linux-headers"
+else
+	BDEPEND+="
+		>=sys-devel/binutils-2.27
+		>=sys-devel/gcc-6.2
+	"
+	DEPEND+=" virtual/os-headers "
+	RDEPEND+="
+		>=net-dns/libidn2-2.3.0
+		vanilla? ( !sys-libs/timezone-data )
+	"
+	PDEPEND+=" !vanilla? ( sys-libs/timezone-data )"
+fi
+
+# Ignore tests whitelisted below
+GENTOO_GLIBC_XFAIL_TESTS="${GENTOO_GLIBC_XFAIL_TESTS:-yes}"
+
+# The following tests fail due to the Gentoo build system and are thus
+# executed but ignored:
+XFAIL_TEST_LIST=(
+	# buggy test, assumes /dev/ and /dev/null on a single filesystem
+	# 'mount --bind /dev/null /chroot/dev/null' breaks it.
+	# https://sourceware.org/PR25909
+	tst-support_descriptors
+
+	# The following tests fail only inside portage
+	# https://bugs.gentoo.org/831267
+	tst-system
+	tst-strerror
+	tst-strsignal
+	# Fails with certain PORTAGE_NICENESS/PORTAGE_SCHEDULING_POLICY
+	tst-sched1
+)
+
+XFAIL_NSPAWN_TEST_LIST=(
+	# These tests need to be adapted to handle EPERM/ENOSYS(?) properly
+	# upstream, as systemd-nspawn's default seccomp whitelist is too strict.
+	# https://sourceware.org/PR30603
+	test-errno-linux
+	tst-bz21269
+	tst-mlock2
+	tst-ntp_gettime
+	tst-ntp_gettime-time64
+	tst-ntp_gettimex
+	tst-ntp_gettimex-time64
+	tst-pkey
+	tst-process_mrelease
+	tst-adjtime
+	tst-adjtime-time64
+	tst-clock2
+	tst-clock2-time64
+
+	# These fail if --suppress-sync and/or low priority is set
+	tst-sync_file_range
+	test-errno
+)
+
+#
+# Small helper functions
+#
+
+dump_build_environment() {
+	einfo ==== glibc build environment ========================================================
+	local v
+	for v in ABI CBUILD CHOST CTARGET CBUILD_OPT CTARGET_OPT CC CXX CPP LD {AS,C,CPP,CXX,LD}FLAGS MAKEINFO NM AR AS STRIP RANLIB OBJCOPY STRINGS OBJDUMP READELF; do
+		einfo " $(printf '%15s' ${v}:)   ${!v}"
+	done
+	einfo =====================================================================================
+}
+
+is_crosscompile() {
+	[[ ${CHOST} != ${CTARGET} ]]
+}
+
+just_headers() {
+	is_crosscompile && use headers-only
+}
+
+alt_prefix() {
+	is_crosscompile && echo /usr/${CTARGET}
+}
+
+# This prefix is applicable to CHOST when building against this
+# glibc. It is baked into the library at configure time.
+host_eprefix() {
+	is_crosscompile || echo "${EPREFIX}"
+}
+
+# This prefix is applicable to CBUILD when building against this
+# glibc. It determines the destination path at install time.
+build_eprefix() {
+	is_crosscompile && echo "${EPREFIX}"
+}
+
+# We need to be able to set alternative headers for compiling for non-native
+# platform. Will also become useful for testing kernel-headers without screwing
+# up the whole system.
+alt_headers() {
+	echo ${ALT_HEADERS:=$(alt_prefix)/usr/include}
+}
+
+alt_build_headers() {
+	if [[ -z ${ALT_BUILD_HEADERS} ]] ; then
+		ALT_BUILD_HEADERS="$(host_eprefix)$(alt_headers)"
+		if tc-is-cross-compiler ; then
+			ALT_BUILD_HEADERS=${SYSROOT}$(alt_headers)
+			if [[ ! -e ${ALT_BUILD_HEADERS}/linux/version.h ]] ; then
+				local header_path=$(echo '#include <linux/version.h>' | $(tc-getCPP ${CTARGET}) ${CFLAGS} 2>&1 | grep -o '[^"]*linux/version.h')
+				ALT_BUILD_HEADERS=${header_path%/linux/version.h}
+			fi
+		fi
+	fi
+	echo "${ALT_BUILD_HEADERS}"
+}
+
+alt_libdir() {
+	echo $(alt_prefix)/$(get_libdir)
+}
+alt_usrlibdir() {
+	echo $(alt_prefix)/usr/$(get_libdir)
+}
+
+builddir() {
+	echo "${WORKDIR}/build-${ABI}-${CTARGET}-$1"
+}
+
+do_compile_test() {
+	local ret save_cflags=${CFLAGS}
+	CFLAGS+=" $1"
+	shift
+
+	pushd "${T}" >/dev/null
+
+	rm -f glibc-test*
+	printf '%b' "$*" > glibc-test.c
+
+	# We assume CC is already set up.
+	nonfatal emake glibc-test
+	ret=$?
+
+	popd >/dev/null
+
+	CFLAGS=${save_cflags}
+	return ${ret}
+}
+
+do_run_test() {
+	local ret
+
+	if [[ ${MERGE_TYPE} == "binary" ]] ; then
+		# ignore build failures when installing a binary package #324685
+		do_compile_test "" "$@" 2>/dev/null || return 0
+	else
+		if ! do_compile_test "" "$@" ; then
+			ewarn "Simple build failed ... assuming this is desired #324685"
+			return 0
+		fi
+	fi
+
+	pushd "${T}" >/dev/null
+
+	./glibc-test
+	ret=$?
+	rm -f glibc-test*
+
+	popd >/dev/null
+
+	return ${ret}
+}
+
+setup_target_flags() {
+	# This largely mucks with compiler flags.  None of which should matter
+	# when building up just the headers.
+	just_headers && return 0
+
+	case $(tc-arch) in
+		x86)
+			# -march needed for #185404 #199334
+			# TODO: When creating the first glibc cross-compile, this test will
+			# always fail as it does a full link which in turn requires glibc.
+			# Probably also applies when changing multilib profile settings (e.g.
+			# enabling x86 when the profile was amd64-only previously).
+			# We could change main to _start and pass -nostdlib here so that we
+			# only test the gcc code compilation.  Or we could do a compile and
+			# then look for the symbol via scanelf.
+			if ! do_compile_test "" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n'; then
+				local t=${CTARGET_OPT:-${CTARGET}}
+				t=${t%%-*}
+				filter-flags '-march=*'
+				export CFLAGS="-march=${t} ${CFLAGS}"
+				einfo "Auto adding -march=${t} to CFLAGS #185404"
+			fi
+			# For compatibility with older binaries at slight performance cost.
+			use stack-realign && export CFLAGS+=" -mstackrealign"
+		;;
+		amd64)
+			# -march needed for #185404 #199334
+			# TODO: See cross-compile issues listed above for x86.
+			if [[ ${ABI} == x86 ]]; then
+				if ! do_compile_test "${CFLAGS_x86}" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n'; then
+					local t=${CTARGET_OPT:-${CTARGET}}
+					t=${t%%-*}
+					# Normally the target is x86_64-xxx, so turn that into the -march that
+					# gcc actually accepts. #528708
+					[[ ${t} == "x86_64" ]] && t="x86-64"
+					filter-flags '-march=*'
+					# ugly, ugly, ugly.  ugly.
+					CFLAGS_x86=$(CFLAGS=${CFLAGS_x86} filter-flags '-march=*'; echo "${CFLAGS}")
+					export CFLAGS_x86="${CFLAGS_x86} -march=${t}"
+					einfo "Auto adding -march=${t} to CFLAGS_x86 #185404 (ABI=${ABI})"
+				fi
+				# For compatibility with older binaries at slight performance cost.
+				use stack-realign && export CFLAGS_x86+=" -mstackrealign"
+
+				# Workaround for bug #823780.
+				# Need to save/restore CC because earlier on, we stuff it full of CFLAGS, and tc-getCPP doesn't like that.
+				CC_mangled=${CC}
+				CC=${glibc__GLIBC_CC}
+				if tc-is-gcc && (($(gcc-major-version) == 11)) && (($(gcc-minor-version) <= 2)) && (($(gcc-micro-version) == 0)) ; then
+					export CFLAGS_x86="${CFLAGS_x86} -mno-avx512f"
+					einfo "Auto adding -mno-avx512f to CFLAGS_x86 for buggy GCC version (bug #823780) (ABI=${ABI})"
+				fi
+				CC=${CC_mangled}
+			fi
+		;;
+		mips)
+			# The mips abi cannot support the GNU style hashes. #233233
+			filter-ldflags -Wl,--hash-style=gnu -Wl,--hash-style=both
+		;;
+		ppc|ppc64)
+			# Many arch-specific implementations do not work on ppc with
+			# cache-block not equal to 128 bytes. This breaks memset:
+			#   https://sourceware.org/PR26522
+			#   https://bugs.gentoo.org/737996
+			# Use default -mcpu=. For ppc it means non-multiarch setup.
+			filter-flags '-mcpu=*'
+		;;
+		sparc)
+			# Both sparc and sparc64 can use -fcall-used-g6.  -g7 is bad, though.
+			filter-flags "-fcall-used-g7"
+			append-flags "-fcall-used-g6"
+
+			local cpu
+			case ${CTARGET} in
+			sparc64-*)
+				cpu="sparc64"
+				case $(get-flag mcpu) in
+				v9)
+					# We need to force at least v9a because the base build doesn't
+					# work with just v9.
+					# https://sourceware.org/bugzilla/show_bug.cgi?id=19477
+					append-flags "-Wa,-xarch=v9a"
+					;;
+				esac
+				;;
+			sparc-*)
+				case $(get-flag mcpu) in
+				v8|supersparc|hypersparc|leon|leon3)
+					cpu="sparcv8"
+					;;
+				*)
+					cpu="sparcv9"
+					;;
+				esac
+			;;
+			esac
+			[[ -n ${cpu} ]] && CTARGET_OPT="${cpu}-${CTARGET#*-}"
+		;;
+	esac
+}
+
+setup_flags() {
+	# Make sure host make.conf doesn't pollute us
+	if is_crosscompile || tc-is-cross-compiler ; then
+		CHOST=${CTARGET} strip-unsupported-flags
+	fi
+
+	# Store our CFLAGS because it's changed depending on which CTARGET
+	# we are building when pulling glibc on a multilib profile
+	CFLAGS_BASE=${CFLAGS_BASE-${CFLAGS}}
+	CFLAGS=${CFLAGS_BASE}
+	CXXFLAGS_BASE=${CXXFLAGS_BASE-${CXXFLAGS}}
+	CXXFLAGS=${CXXFLAGS_BASE}
+	ASFLAGS_BASE=${ASFLAGS_BASE-${ASFLAGS}}
+	ASFLAGS=${ASFLAGS_BASE}
+
+	# Allow users to explicitly avoid flag sanitization via
+	# USE=custom-cflags.
+	if ! use custom-cflags; then
+		# Over-zealous CFLAGS can often cause problems.  What may work for one
+		# person may not work for another.  To avoid a large influx of bugs
+		# relating to failed builds, we strip most CFLAGS out to ensure as few
+		# problems as possible.
+		strip-flags
+		# Lock glibc at -O2; we want to be conservative here.
+		filter-flags '-O?'
+		append-flags -O2
+	fi
+
+	strip-unsupported-flags
+	filter-lto
+	filter-flags -m32 -m64 '-mabi=*'
+
+	# glibc aborts if rpath is set by LDFLAGS
+	filter-ldflags '-Wl,-rpath=*'
+
+	# ld can't use -r & --relax at the same time, bug #788901
+	# https://sourceware.org/PR27837
+	filter-ldflags '-Wl,--relax'
+
+	# Flag added for cross-prefix, but causes ldconfig to segfault. Not needed
+	# anyway because glibc already handles this by itself.
+	filter-ldflags '-Wl,--dynamic-linker=*'
+
+	# some weird software relies on sysv hashes in glibc, bug 863863, bug 864100
+	# we have to do that here already so mips can filter it out again :P
+	if use hash-sysv-compat ; then
+		append-ldflags '-Wl,--hash-style=both'
+	fi
+
+	# #492892
+	filter-flags -frecord-gcc-switches
+
+	# #898098
+	filter-flags -fno-builtin
+
+	# #829583
+	filter-lfs-flags
+
+	unset CBUILD_OPT CTARGET_OPT
+	if use multilib ; then
+		CTARGET_OPT=$(get_abi_CTARGET)
+		[[ -z ${CTARGET_OPT} ]] && CTARGET_OPT=$(get_abi_CHOST)
+	fi
+
+	setup_target_flags
+
+	if [[ -n ${CTARGET_OPT} && ${CBUILD} == ${CHOST} ]] && ! is_crosscompile; then
+		CBUILD_OPT=${CTARGET_OPT}
+	fi
+
+	# glibc's headers disallow -O0 and fail at build time:
+	#  include/libc-symbols.h:75:3: #error "glibc cannot be compiled without optimization"
+	# https://sourceware.org/glibc/wiki/FAQ#Why_do_I_get:.60.23error_.22glibc_cannot_be_compiled_without_optimization.22.27.2C_when_trying_to_compile_GNU_libc_with_GNU_CC.3F
+	replace-flags -O0 -O1
+
+	# glibc handles this internally already where it's appropriate;
+	# can't always have SSP when we're the ones setting it up, etc
+	filter-flags '-fstack-protector*'
+
+	# Similar issues as with SSP. Can't inject yourself that early.
+	filter-flags '-fsanitize=*'
+
+	# See end of bug #830454; we handle this via USE=cet
+	filter-flags '-fcf-protection=*'
+
+	# When bootstrapping, we may have a situation where
+	# CET-enabled gcc from seed is used to build CET-disabled
+	# glibc. As such, gcc implicitly enables CET if no
+	# -fcf-protection flag is passed. For a typical package it
+	# should not be a problem, but for glibc it matters as it is
+	# dealing with CET in ld.so. So if CET is supposed to be
+	# disabled for glibc, be explicit about it.
+	if (use amd64 || use x86) && ! use cet; then
+		append-flags '-fcf-protection=none'
+	fi
+}
+
+use_multiarch() {
+	# Allow user to disable runtime arch detection in multilib.
+	use multiarch || return 1
+	# Make sure binutils is new enough to support indirect functions,
+	# #336792. This funky sed supports gold and bfd linkers.
+	local bver nver
+	bver=$($(tc-getLD ${CTARGET}) -v | sed -n -r '1{s:[^0-9]*::;s:^([0-9.]*).*:\1:;p}')
+	case $(tc-arch ${CTARGET}) in
+	amd64|x86) nver="2.20" ;;
+	arm)       nver="2.22" ;;
+	hppa)      nver="2.23" ;;
+	ppc|ppc64) nver="2.20" ;;
+	# ifunc support was added in 2.23, but glibc also needs
+	# machinemode which is in 2.24.
+	s390)      nver="2.24" ;;
+	sparc)     nver="2.21" ;;
+	*)         return 1 ;;
+	esac
+	ver_test ${bver} -ge ${nver}
+}
+
+# Setup toolchain variables that had historically been defined in the
+# profiles for these archs.
+setup_env() {
+	# silly users
+	unset LD_RUN_PATH
+	unset LD_ASSUME_KERNEL
+
+	if is_crosscompile || tc-is-cross-compiler ; then
+		multilib_env ${CTARGET_OPT:-${CTARGET}}
+
+		if ! use multilib ; then
+			MULTILIB_ABIS=${DEFAULT_ABI}
+		else
+			MULTILIB_ABIS=${MULTILIB_ABIS:-${DEFAULT_ABI}}
+		fi
+
+		# If the user has CFLAGS_<CTARGET> in their make.conf, use that,
+		# and fall back on CFLAGS.
+		local VAR=CFLAGS_${CTARGET//[-.]/_}
+		CFLAGS=${!VAR-${CFLAGS}}
+		einfo " $(printf '%15s' 'Manual CFLAGS:')   ${CFLAGS}"
+	fi
+
+	setup_flags
+
+	export ABI=${ABI:-${DEFAULT_ABI:-default}}
+
+	if just_headers ; then
+		# Avoid mixing host's CC and target's CFLAGS_${ABI}:
+		# At this bootstrap stage we have only binutils for
+		# target but not compiler yet.
+		einfo "Skip CC ABI injection. We can't use (cross-)compiler yet."
+		return 0
+	fi
+
+	# Glibc does not work with gold (for various reasons) #269274.
+	tc-ld-disable-gold
+
+	if use doc ; then
+		export MAKEINFO=makeinfo
+	else
+		export MAKEINFO=/dev/null
+	fi
+
+	# Reset CC and CXX to the value at start of emerge
+	export CC=${glibc__ORIG_CC:-${CC:-$(tc-getCC ${CTARGET})}}
+	export CXX=${glibc__ORIG_CXX:-${CXX:-$(tc-getCXX ${CTARGET})}}
+
+	# and make sure glibc__ORIG_CC and glibc__ORIG_CXX is defined now.
+	export glibc__ORIG_CC=${CC}
+	export glibc__ORIG_CXX=${CXX}
+
+	if tc-is-clang && ! use custom-cflags && ! is_crosscompile ; then
+		export glibc__force_gcc=yes
+		# once this is toggled on, it needs to stay on, since with CPP manipulated
+		# tc-is-clang does not work correctly anymore...
+	fi
+
+	if [[ ${glibc__force_gcc} == "yes" ]] ; then
+		# If we are running in an otherwise clang/llvm environment, we need to
+		# recover the proper gcc and binutils settings here, at least until glibc
+		# is finally building with clang. So let's override everything that is
+		# set in the clang profiles.
+		# Want to shoot yourself into the foot? Set USE=custom-cflags, that's always
+		# a good start into that direction.
+		# Also, if you're crosscompiling, let's assume you know what you are doing.
+		# Hopefully.
+		# Last, we need the settings of the *build* environment, not of the
+		# target environment...
+
+		local current_binutils_path=$(env ROOT="${BROOT}" binutils-config -B)
+		local current_gcc_path=$(env ROOT="${BROOT}" gcc-config -B)
+		einfo "Overriding clang configuration, since it won't work here"
+
+		export CC="${current_gcc_path}/gcc"
+		export CPP="${current_gcc_path}/cpp"
+		export CXX="${current_gcc_path}/g++"
+		export LD="${current_binutils_path}/ld.bfd"
+		export AR="${current_binutils_path}/ar"
+		export AS="${current_binutils_path}/as"
+		export NM="${current_binutils_path}/nm"
+		export STRIP="${current_binutils_path}/strip"
+		export RANLIB="${current_binutils_path}/ranlib"
+		export OBJCOPY="${current_binutils_path}/objcopy"
+		export STRINGS="${current_binutils_path}/strings"
+		export OBJDUMP="${current_binutils_path}/objdump"
+		export READELF="${current_binutils_path}/readelf"
+		export ADDR2LINE="${current_binutils_path}/addr2line"
+
+		# do we need to also do flags munging here? yes! at least...
+		filter-flags '-fuse-ld=*'
+		filter-flags '-D_FORTIFY_SOURCE=*'
+
+	else
+
+		# this is the "normal" case
+
+		export CC="$(tc-getCC ${CTARGET})"
+		export CXX="$(tc-getCXX ${CTARGET})"
+
+		# Always use tuple-prefixed toolchain. For non-native ABI glibc's configure
+		# can't detect them automatically due to ${CHOST} mismatch and fallbacks
+		# to unprefixed tools. Similar to multilib.eclass:multilib_toolchain_setup().
+		export NM="$(tc-getNM ${CTARGET})"
+		export READELF="$(tc-getREADELF ${CTARGET})"
+
+	fi
+
+	# We need to export CFLAGS with abi information in them because glibc's
+	# configure script checks CFLAGS for some targets (like mips).  Keep
+	# around the original clean value to avoid appending multiple ABIs on
+	# top of each other. (Why does the comment talk about CFLAGS if the code
+	# acts on CC?)
+	export glibc__GLIBC_CC=${CC}
+	export glibc__GLIBC_CXX=${CXX}
+
+	export glibc__abi_CFLAGS="$(get_abi_CFLAGS)"
+
+	# CFLAGS can contain ABI-specific flags like -mfpu=neon, see bug #657760
+	# To build .S (assembly) files with the same ABI-specific flags
+	# upstream currently recommends adding CFLAGS to CC/CXX:
+	#    https://sourceware.org/PR23273
+	# Note: Passing CFLAGS via CPPFLAGS overrides glibc's arch-specific CFLAGS
+	# and breaks multiarch support. See 659030#c3 for an example.
+	# The glibc configure script doesn't properly use LDFLAGS all the time.
+	export CC="${glibc__GLIBC_CC} ${glibc__abi_CFLAGS} ${CFLAGS} ${LDFLAGS}"
+
+	# Some of the tests are written in C++, so we need to force our multlib abis in, bug 623548
+	export CXX="${glibc__GLIBC_CXX} ${glibc__abi_CFLAGS} ${CFLAGS}"
+
+	if is_crosscompile; then
+		# Assume worst-case bootstrap: glibc is built for the first time
+		# with ${CTARGET}-g++ not available yet. We avoid
+		# building auxiliary programs that require C++: bug #683074
+		# It should not affect final result.
+		export libc_cv_cxx_link_ok=no
+		# The line above has the same effect. We set CXX explicitly
+		# to make build logs less confusing.
+		export CXX=
+	fi
+}
+
+foreach_abi() {
+	setup_env
+
+	local ret=0
+	local abilist=""
+	if use multilib ; then
+		abilist=$(get_install_abis)
+	else
+		abilist=${DEFAULT_ABI}
+	fi
+	local -x ABI
+	for ABI in ${abilist:-default} ; do
+		setup_env
+		einfo "Running $1 for ABI ${ABI}"
+		$1
+		: $(( ret |= $? ))
+	done
+	return ${ret}
+}
+
+glibc_banner() {
+	local b="Gentoo ${PVR}"
+	[[ -n ${PATCH_VER} ]] && ! use vanilla && b+=" (patchset ${PATCH_VER})"
+	echo "${b}"
+}
+
+# The following Kernel version handling functions are mostly copied from portage
+# source. It's better not to use linux-info.eclass here since a) it adds too
+# much magic, see bug 326693 for some of the arguments, and b) some of the
+# functions are just not provided.
+
+g_get_running_KV() {
+	uname -r
+	return $?
+}
+
+g_KV_major() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	echo "${KV%%.*}"
+}
+
+g_KV_minor() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	KV=${KV#*.}
+	echo "${KV%%.*}"
+}
+
+g_KV_micro() {
+	[[ -z $1 ]] && return 1
+	local KV=$@
+	KV=${KV#*.*.}
+	echo "${KV%%[^[:digit:]]*}"
+}
+
+g_KV_to_int() {
+	[[ -z $1 ]] && return 1
+	local KV_MAJOR=$(g_KV_major "$1")
+	local KV_MINOR=$(g_KV_minor "$1")
+	local KV_MICRO=$(g_KV_micro "$1")
+	local KV_int=$(( KV_MAJOR * 65536 + KV_MINOR * 256 + KV_MICRO ))
+
+	# We make version 2.2.0 the minimum version we will handle as
+	# a sanity check ... if its less, we fail ...
+	if [[ ${KV_int} -ge 131584 ]] ; then
+		echo "${KV_int}"
+		return 0
+	fi
+	return 1
+}
+
+g_int_to_KV() {
+	local version=$1 major minor micro
+	major=$((version / 65536))
+	minor=$(((version % 65536) / 256))
+	micro=$((version % 256))
+	echo ${major}.${minor}.${micro}
+}
+
+eend_KV() {
+	[[ $(g_KV_to_int $1) -ge $(g_KV_to_int $2) ]]
+	eend $?
+}
+
+get_kheader_version() {
+	printf '#include <linux/version.h>\nLINUX_VERSION_CODE\n' | \
+	$(tc-getCPP ${CTARGET}) -I "$(build_eprefix)$(alt_build_headers)" - | \
+	tail -n 1
+}
+
+# We collect all sanity checks here. Consistency is not guranteed between
+# pkg_ and src_ phases, so we call this function both in pkg_pretend and in
+# src_unpack.
+sanity_prechecks() {
+	# Prevent native builds from downgrading
+	if [[ ${MERGE_TYPE} != "buildonly" ]] && \
+	   [[ -z ${ROOT} ]] && \
+	   [[ ${CBUILD} == ${CHOST} ]] && \
+	   [[ ${CHOST} == ${CTARGET} ]] ; then
+
+		# The high rev # is to allow people to downgrade between -r#
+		# versions. We want to block 2.20->2.19, but 2.20-r3->2.20-r2
+		# should be fine. Hopefully we never actually use a r# this
+		# high.
+		if has_version ">${CATEGORY}/${P}-r10000" ; then
+			eerror "Sanity check to keep you from breaking your system:"
+			eerror " Downgrading glibc is not supported and a sure way to destruction."
+			[[ ${I_ALLOW_TO_BREAK_MY_SYSTEM} = yes ]] || die "Aborting to save your system."
+		fi
+
+		if ! do_run_test '#include <unistd.h>\n#include <sys/syscall.h>\nint main(){return syscall(1000)!=-1;}\n' ; then
+			eerror "Your old kernel is broken. You need to update it to a newer"
+			eerror "version as syscall(<bignum>) will break. See bug 279260."
+			die "Old and broken kernel."
+		fi
+	fi
+
+	if [[ ${CTARGET} == i386-* ]] ; then
+		eerror "i386 CHOSTs are no longer supported."
+		eerror "Chances are you don't actually want/need i386."
+		eerror "Please read https://www.gentoo.org/doc/en/change-chost.xml"
+		die "Please fix your CHOST"
+	fi
+
+	if [[ -e /proc/xen ]] && [[ $(tc-arch) == "x86" ]] && ! is-flag -mno-tls-direct-seg-refs ; then
+		ewarn "You are using Xen but don't have -mno-tls-direct-seg-refs in your CFLAGS."
+		ewarn "This will result in a 50% performance penalty when running with a 32bit"
+		ewarn "hypervisor, which is probably not what you want."
+	fi
+
+	# ABI-specific checks follow here. Hey, we have a lot more specific conditions that
+	# we test for...
+	if ! is_crosscompile ; then
+		if use amd64 && use multilib && [[ ${MERGE_TYPE} != "binary" ]] ; then
+			ebegin "Checking that IA32 emulation is enabled in the running kernel"
+			echo 'int main(){return 0;}' > "${T}/check-ia32-emulation.c"
+			local STAT
+			if ${CC-${CHOST}-gcc} ${CFLAGS_x86} "${T}/check-ia32-emulation.c" -o "${T}/check-ia32-emulation.elf32"; then
+				"${T}/check-ia32-emulation.elf32"
+				STAT=$?
+			else
+				# Don't fail here to allow single->multi ABI switch
+				# or recover from breakage like bug #646424
+				ewarn "Failed to compile the ABI test. Broken host glibc?"
+				STAT=0
+			fi
+			rm -f "${T}/check-ia32-emulation.elf32"
+			eend $STAT
+			[[ $STAT -eq 0 ]] || die "CONFIG_IA32_EMULATION must be enabled in the kernel to compile a multilib glibc."
+		fi
+
+	fi
+
+	# When we actually have to compile something...
+	if ! just_headers && [[ ${MERGE_TYPE} != "binary" ]] ; then
+		if [[ -d "${ESYSROOT}"/usr/lib/include ]] ; then
+			# bug #833620, bug #643302
+			eerror "Found ${ESYSROOT}/usr/lib/include directory!"
+			eerror "This is known to break glibc's build."
+			eerror "Please backup its contents then remove the directory."
+			die "Found directory (${ESYSROOT}/usr/lib/include) which will break build (bug #833620)!"
+		fi
+
+		if [[ ${CTARGET} == *-linux* ]] ; then
+			local run_kv build_kv want_kv
+
+			run_kv=$(g_get_running_KV)
+			build_kv=$(g_int_to_KV $(get_kheader_version))
+			want_kv=${MIN_KERN_VER}
+
+			if ! is_crosscompile && ! tc-is-cross-compiler ; then
+				# Building fails on an non-supporting kernel
+				ebegin "Checking running kernel version (${run_kv} >= ${want_kv})"
+				if ! eend_KV ${run_kv} ${want_kv} ; then
+					echo
+					eerror "You need a kernel of at least ${want_kv}!"
+					die "Kernel version too low!"
+				fi
+			fi
+
+			# Do not run this check for pkg_pretend, just pkg_setup and friends (if we ever get used there).
+			# It's plausible (seen it in the wild) that Portage will (correctly) schedule a linux-headers
+			# upgrade before glibc, but because pkg_pretend gets run before any packages are merged at all (not
+			# just glibc), the whole emerge gets aborted without a good reason. We probably don't
+			# need to run this check at all given we have a dependency on the right headers,
+			# but let's leave it as-is for now.
+			if [[ ${EBUILD_PHASE_FUNC} != pkg_pretend ]] ; then
+				ebegin "Checking linux-headers version (${build_kv} >= ${want_kv})"
+				if ! eend_KV ${build_kv} ${want_kv} ; then
+					echo
+					eerror "You need linux-headers of at least ${want_kv}!"
+					die "linux-headers version too low!"
+				fi
+			fi
+		fi
+	fi
+}
+
+upgrade_warning() {
+	is_crosscompile && return
+
+	if [[ ${MERGE_TYPE} != buildonly && -n ${REPLACING_VERSIONS} && -z ${ROOT} ]]; then
+		local oldv newv=$(ver_cut 1-2 ${PV})
+		for oldv in ${REPLACING_VERSIONS}; do
+			if ver_test ${oldv} -lt ${newv}; then
+				ewarn "After upgrading glibc, please restart all running processes."
+				ewarn "Be sure to include init (telinit u) or systemd (systemctl daemon-reexec)."
+				ewarn "Alternatively, reboot your system."
+				ewarn "(See bug #660556, bug #741116, bug #823756, etc)"
+				break
+			fi
+		done
+	fi
+}
+
+#
+# the phases
+#
+
+# pkg_pretend
+
+pkg_pretend() {
+	upgrade_warning
+}
+
+# pkg_setup
+
+pkg_setup() {
+	# see bug 682570
+	[[ -z ${BOOTSTRAP_RAP} ]] && python-any-r1_pkg_setup
+}
+
+# src_unpack
+
+src_unpack() {
+	setup_env
+
+	einfo "Checking general environment sanity."
+	sanity_prechecks
+
+	use multilib-bootstrap && unpack gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz
+
+	if [[ ${PV} == 9999* ]] ; then
+		EGIT_REPO_URI="https://anongit.gentoo.org/git/proj/toolchain/glibc-patches.git"
+		EGIT_CHECKOUT_DIR=${WORKDIR}/patches-git
+		git-r3_src_unpack
+		mv patches-git/9999 patches || die
+
+		EGIT_REPO_URI="https://sourceware.org/git/glibc.git"
+		EGIT_CHECKOUT_DIR=${S}
+		git-r3_src_unpack
+	else
+		unpack ${P}.tar.xz
+
+		cd "${WORKDIR}" || die
+		unpack glibc-${PV}-patches-${PATCH_VER}.tar.xz
+	fi
+
+	cd "${WORKDIR}" || die
+	use systemd && unpack glibc-systemd-${GLIBC_SYSTEMD_VER}.tar.gz
+}
+
+# src_prepare
+
+src_prepare() {
+	local patchsetname
+	if ! use vanilla ; then
+		if [[ ${PV} == 9999* ]] ; then
+			patchsetname="from git master"
+		else
+			patchsetname="${PV}-${PATCH_VER}"
+		fi
+		einfo "Applying Gentoo Glibc patchset ${patchsetname}"
+		eapply "${WORKDIR}"/patches
+		einfo "Done."
+	fi
+
+	default
+
+	gnuconfig_update
+
+	cd "${WORKDIR}" || die
+	find . -name configure -exec touch {} +
+
+	# Fix permissions on some of the scripts.
+	chmod u+x "${S}"/scripts/*.sh
+
+	cd "${S}" || die
+}
+
+# src_configure
+
+glibc_do_configure() {
+	dump_build_environment
+
+	local myconf=()
+
+	# Use '=strong' instead of '=all' to protect only functions
+	# worth protecting from stack smashes.
+	myconf+=( --enable-stack-protector=$(usex ssp strong no) )
+
+	# Keep a whitelist of targets supporing IFUNC. glibc's ./configure
+	# is not robust enough to detect proper support:
+	#    https://bugs.gentoo.org/641216
+	#    https://sourceware.org/PR22634#c0
+	case $(tc-arch ${CTARGET}) in
+		# Keep whitelist of targets where autodetection mostly works.
+		amd64|x86|sparc|ppc|ppc64|arm|arm64|s390|riscv|loong) ;;
+		# Blacklist everywhere else
+		*) myconf+=( libc_cv_ld_gnu_indirect_function=no ) ;;
+	esac
+
+	# Enable Intel Control-flow Enforcement Technology on amd64 if requested
+	case ${CTARGET} in
+		x86_64-*) myconf+=( $(use_enable cet) ) ;;
+		*) ;;
+	esac
+
+	[[ $(tc-is-softfloat) == "yes" ]] && myconf+=( --without-fp )
+
+	myconf+=( --enable-kernel=${MIN_KERN_VER} )
+
+	# Since SELinux support is only required for nscd, only enable it if:
+	# 1. USE selinux
+	# 2. only for the primary ABI on multilib systems
+	# 3. Not a crosscompile
+	if ! is_crosscompile && use selinux ; then
+		if use multilib ; then
+			if is_final_abi ; then
+				myconf+=( --with-selinux )
+			else
+				myconf+=( --without-selinux )
+			fi
+		else
+			myconf+=( --with-selinux )
+		fi
+	else
+		myconf+=( --without-selinux )
+	fi
+
+	# Force a few tests where we always know the answer but
+	# configure is incapable of finding it.
+	if is_crosscompile ; then
+		export \
+			libc_cv_c_cleanup=yes \
+			libc_cv_forced_unwind=yes
+	fi
+
+	myconf+=(
+		--disable-werror
+		--enable-bind-now
+		--enable-fortify-source
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		$(use_enable profile)
+		$(use_with gd)
+		--with-headers=$(build_eprefix)$(alt_build_headers)
+		--prefix="$(host_eprefix)/usr"
+		--sysconfdir="$(host_eprefix)/etc"
+		--localstatedir="$(host_eprefix)/var"
+		--libdir='$(prefix)'/$(get_libdir)
+		--mandir='$(prefix)'/share/man
+		--infodir='$(prefix)'/share/info
+		--libexecdir='$(libdir)'/misc/glibc
+		--with-bugurl=https://bugs.gentoo.org/
+		--with-pkgversion="$(glibc_banner)"
+		$(use_enable crypt)
+		$(use_multiarch || echo --disable-multi-arch)
+		$(use_enable systemtap)
+		$(use_enable nscd)
+
+		# /usr/bin/mtrace has a Perl shebang. Gentoo Prefix QA checks fail if
+		# Perl hasn't been installed inside the prefix yet and configure picks
+		# up a Perl from outside the prefix instead. configure will fail to
+		# execute Perl during configure if we're cross-compiling a prefix, but
+		# it will just disable mtrace in that case.
+		# Note: mtrace is needed by the test suite.
+		ac_cv_path_PERL="$(usex perl "${EPREFIX}"/usr/bin/perl $(usex test "${EPREFIX}"/usr/bin/perl $(usex doc "${EPREFIX}"/usr/bin/perl no)))"
+
+		# locale data is arch-independent
+		# https://bugs.gentoo.org/753740
+		libc_cv_complocaledir='${exec_prefix}/lib/locale'
+
+		# On aarch64 there is no way to override -mcpu=native, and if
+		# the current cpu does not support SVE configure fails.
+		# Let's boldly assume our toolchain can always build SVE instructions.
+		libc_cv_aarch64_sve_asm=yes
+
+		${EXTRA_ECONF}
+	)
+
+	# We rely on sys-libs/timezone-data for timezone tools normally.
+	myconf+=( $(use_enable vanilla timezone-tools) )
+
+	# These libs don't have configure flags.
+	ac_cv_lib_audit_audit_log_user_avc_message=$(usex audit || echo no)
+	ac_cv_lib_cap_cap_init=$(usex caps || echo no)
+
+	# There is no configure option for this and we need to export it
+	# since the glibc build will re-run configure on itself
+	export libc_cv_rootsbindir="$(host_eprefix)/sbin"
+	export libc_cv_slibdir="$(host_eprefix)/$(get_libdir)"
+
+	local builddir=$(builddir nptl)
+	mkdir -p "${builddir}"
+	cd "${builddir}"
+	set -- "${S}"/configure "${myconf[@]}"
+	echo "$@"
+	"$@" || die "failed to configure glibc"
+
+	# ia64 static cross-compilers are a pita in so much that they
+	# can't produce static ELFs (as the libgcc.a is broken).  so
+	# disable building of the programs for those targets if it
+	# doesn't work.
+	# XXX: We could turn this into a compiler test, but ia64 is
+	# the only one that matters, so this should be fine for now.
+	if is_crosscompile && [[ ${CTARGET} == ia64* ]] ; then
+		sed -i '1i+link-static = touch $@' config.make
+	fi
+
+	# If we're trying to migrate between ABI sets, we need
+	# to lie and use a local copy of gcc.  Like if the system
+	# is built with MULTILIB_ABIS="amd64 x86" but we want to
+	# add x32 to it, gcc/glibc don't yet support x32.
+	#
+	if [[ -n ${GCC_BOOTSTRAP_VER} ]] && use multilib-bootstrap ; then
+		echo 'int main(void){}' > "${T}"/test.c || die
+		if ! $(tc-getCC ${CTARGET}) ${CFLAGS} ${LDFLAGS} "${T}"/test.c -Wl,-emain -lgcc 2>/dev/null ; then
+			sed -i -e '/^CC = /s:$: -B$(objdir)/../'"gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}/${ABI}:" config.make || die
+		fi
+	fi
+}
+
+glibc_headers_configure() {
+	export ABI=default
+
+	local builddir=$(builddir "headers")
+	mkdir -p "${builddir}"
+	cd "${builddir}"
+
+	# if we don't have a compiler yet, we can't really test it now ...
+	# hopefully they don't affect header generation, so let's hope for
+	# the best here ...
+	local v vars=(
+		ac_cv_header_cpuid_h=yes
+		libc_cv_{386,390,alpha,arm,hppa,ia64,mips,{powerpc,sparc}{,32,64},sh,x86_64}_tls=yes
+		libc_cv_asm_cfi_directives=yes
+		libc_cv_broken_visibility_attribute=no
+		libc_cv_c_cleanup=yes
+		libc_cv_compiler_powerpc64le_binary128_ok=yes
+		libc_cv_forced_unwind=yes
+		libc_cv_gcc___thread=yes
+		libc_cv_mlong_double_128=yes
+		libc_cv_mlong_double_128ibm=yes
+		libc_cv_ppc_machine=yes
+		libc_cv_ppc_rel16=yes
+		libc_cv_predef_fortify_source=no
+		libc_cv_target_power8_ok=yes
+		libc_cv_visibility_attribute=yes
+		libc_cv_z_combreloc=yes
+		libc_cv_z_execstack=yes
+		libc_cv_z_initfirst=yes
+		libc_cv_z_nodelete=yes
+		libc_cv_z_nodlopen=yes
+		libc_cv_z_relro=yes
+		libc_mips_abi=${ABI}
+		libc_mips_float=$([[ $(tc-is-softfloat) == "yes" ]] && echo soft || echo hard)
+		# These libs don't have configure flags.
+		ac_cv_lib_audit_audit_log_user_avc_message=no
+		ac_cv_lib_cap_cap_init=no
+	)
+
+	einfo "Forcing cached settings:"
+	for v in "${vars[@]}" ; do
+		einfo " ${v}"
+		export ${v}
+	done
+
+	local headers_only_arch_CPPFLAGS=()
+
+	# Blow away some random CC settings that screw things up. #550192
+	if [[ -d ${S}/sysdeps/mips ]]; then
+		pushd "${S}"/sysdeps/mips >/dev/null
+		sed -i -e '/^CC +=/s:=.*:= -D_MIPS_SZPTR=32:' mips32/Makefile mips64/n32/Makefile || die
+		sed -i -e '/^CC +=/s:=.*:= -D_MIPS_SZPTR=64:' mips64/n64/Makefile || die
+
+		# Force the mips ABI to the default.  This is OK because the set of
+		# installed headers in this phase is the same between the 3 ABIs.
+		# If this ever changes, this hack will break, but that's unlikely
+		# as glibc discourages that behavior.
+		# https://crbug.com/647033
+		sed -i -e 's:abiflag=.*:abiflag=_ABIO32:' preconfigure || die
+
+		popd >/dev/null
+	fi
+
+	local myconf=()
+
+	case ${CTARGET} in
+	aarch64*)
+		# The configure checks fail during cross-build, so disable here
+		# for headers-only
+		myconf+=(
+			--disable-mathvec
+		) ;;
+	riscv*)
+		# RISC-V interrogates the compiler to determine which target to
+		# build.  If building the headers then we don't strictly need a
+		# RISC-V compiler, so the built-in definitions that are provided
+		# along with all RISC-V compiler might not exist.  This causes
+		# glibc's RISC-V preconfigure script to blow up.  Since we're just
+		# building the headers any value will actually work here, so just
+		# pick the standard one (rv64g/lp64d) to make the build scripts
+		# happy for now -- the headers are all the same anyway so it
+		# doesn't matter.
+		headers_only_arch_CPPFLAGS+=(
+			-D__riscv_xlen=64
+			-D__riscv_flen=64
+			-D__riscv_float_abi_double=1
+			-D__riscv_atomic=1
+		) ;;
+	esac
+
+	myconf+=(
+		--disable-sanity-checks
+		--enable-hacker-mode
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		--with-headers=$(build_eprefix)$(alt_build_headers)
+		--prefix="$(host_eprefix)/usr"
+		$(use_enable crypt)
+		${EXTRA_ECONF}
+	)
+
+	# Nothing is compiled here which would affect the headers for the target.
+	# So forcing CC/CFLAGS is sane.
+	local headers_only_CC=$(tc-getBUILD_CC)
+	local headers_only_CFLAGS="-O1 -pipe"
+	local headers_only_CPPFLAGS="-U_FORTIFY_SOURCE ${headers_only_arch_CPPFLAGS[*]}"
+	local headers_only_LDFLAGS=""
+	set -- "${S}"/configure "${myconf[@]}"
+	echo \
+		"CC=${headers_only_CC}" \
+		"CFLAGS=${headers_only_CFLAGS}" \
+		"CPPFLAGS=${headers_only_CPPFLAGS}" \
+		"LDFLAGS=${headers_only_LDFLAGS}" \
+		"$@"
+	CC=${headers_only_CC} \
+	CFLAGS=${headers_only_CFLAGS} \
+	CPPFLAGS=${headers_only_CPPFLAGS} \
+	LDFLAGS="" \
+	"$@" || die "failed to configure glibc"
+}
+
+do_src_configure() {
+	if just_headers ; then
+		glibc_headers_configure
+	else
+		glibc_do_configure nptl
+	fi
+}
+
+src_configure() {
+	foreach_abi do_src_configure
+}
+
+# src_compile
+
+do_src_compile() {
+	emake -C "$(builddir nptl)"
+}
+
+src_compile() {
+	if just_headers ; then
+		return
+	fi
+
+	foreach_abi do_src_compile
+}
+
+# src_test
+
+glibc_src_test() {
+	cd "$(builddir nptl)"
+
+	local myxfailparams=""
+	if [[ "${GENTOO_GLIBC_XFAIL_TESTS}" == "yes" ]] ; then
+		local virt=$(systemd-detect-virt 2>/dev/null)
+		if [[ ${virt} == systemd-nspawn ]] ; then
+			ewarn "Skipping extra tests because in systemd-nspawn container"
+			XFAIL_TEST_LIST+=( "${XFAIL_NSPAWN_TEST_LIST[@]}" )
+		fi
+
+		for myt in ${XFAIL_TEST_LIST[@]} ; do
+			myxfailparams+="test-xfail-${myt}=yes "
+		done
+	fi
+
+	# sandbox does not understand unshare() and prevents
+	# writes to /proc/, which makes many tests fail
+
+	# we give the tests a bit more time to avoid spurious
+	# bug reports on slow arches
+
+	SANDBOX_ON=0 LD_PRELOAD= TIMEOUTFACTOR=32 emake ${myxfailparams} check
+}
+
+src_test() {
+	if just_headers ; then
+		return
+	fi
+
+	foreach_abi glibc_src_test || die "tests failed"
+}
+
+# src_install
+
+run_locale_gen() {
+	# if the host locales.gen contains no entries, we'll install everything
+	local root="$1"
+	local inplace=""
+
+	if [[ "${root}" == "--inplace-glibc" ]] ; then
+		inplace="--inplace-glibc"
+		root="$2"
+	fi
+
+	local locale_list="${root%/}/etc/locale.gen"
+
+	pushd "${ED}"/$(get_libdir) >/dev/null
+
+	if [[ -z $(locale-gen --list --config "${locale_list}") ]] ; then
+		[[ -z ${inplace} ]] && ewarn "Generating all locales; edit /etc/locale.gen to save time/space"
+		locale_list="${root%/}/usr/share/i18n/SUPPORTED"
+	fi
+
+	# bug 736794: we need to be careful with the parallelization... the number of
+	# processors saved in the environment of a binary package may differ strongly
+	# from the number of processes available during postinst
+	local mygenjobs="$(makeopts_jobs)"
+	if [[ "${EMERGE_FROM}" == "binary" ]] ; then
+		mygenjobs="$(nproc)"
+	fi
+
+	set -- locale-gen ${inplace} --jobs "${mygenjobs}" --config "${locale_list}" \
+		--destdir "${root}"
+	echo "$@"
+	"$@"
+
+	popd >/dev/null
+}
+
+glibc_do_src_install() {
+	local builddir=$(builddir nptl)
+	cd "${builddir}"
+
+	emake install_root="${D}/$(build_eprefix)$(alt_prefix)" install
+
+	# This version (2.26) provides some compatibility libraries for the NIS/NIS+ support
+	# which come without headers etc. Only needed for binary packages since the
+	# external net-libs/libnsl has increased soversion. Keep only versioned libraries.
+	find "${D}" -name "libnsl.a" -delete
+	find "${D}" -name "libnsl.so" -delete
+
+	# Normally upstream_pv is ${PV}. Live ebuilds are exception, there we need
+	# to infer upstream version:
+	# '#define VERSION "2.26.90"' -> '2.26.90'
+	local upstream_pv=$(sed -n -r 's/#define VERSION "(.*)"/\1/p' "${S}"/version.h)
+
+	# Avoid stripping binaries not targeted by ${CHOST}. Or else
+	# ${CHOST}-strip would break binaries build for ${CTARGET}.
+	is_crosscompile && dostrip -x /
+
+	# gdb thread introspection relies on local libpthreads symbols. stripping breaks it
+	# See Note [Disable automatic stripping]
+	dostrip -x $(alt_libdir)/libpthread-${upstream_pv}.so
+	# valgrind requires knowledge about ld.so symbols.
+	dostrip -x $(alt_libdir)/ld-*.so*
+
+	if [[ -e ${ED}/$(alt_usrlibdir)/libm-${upstream_pv}.a ]] ; then
+		# Move versioned .a file out of libdir to evade portage QA checks
+		# instead of using gen_usr_ldscript(). We fix ldscript as:
+		# "GROUP ( /usr/lib64/libm-<pv>.a ..." -> "GROUP ( /usr/lib64/glibc-<pv>/libm-<pv>.a ..."
+		sed -i "s@\(libm-${upstream_pv}.a\)@${P}/\1@" "${ED}"/$(alt_usrlibdir)/libm.a || die
+		dodir $(alt_usrlibdir)/${P}
+		mv "${ED}"/$(alt_usrlibdir)/libm-${upstream_pv}.a "${ED}"/$(alt_usrlibdir)/${P}/libm-${upstream_pv}.a || die
+	fi
+
+	# We configure toolchains for standalone prefix systems with a sysroot,
+	# which is prepended to paths in ld scripts, so strip the prefix from these.
+	# Before: GROUP ( /foo/lib64/libc.so.6 /foo/usr/lib64/libc_nonshared.a  AS_NEEDED ( /foo/lib64/ld-linux-x86-64.so.2 ) )
+	# After: GROUP ( /lib64/libc.so.6 /usr/lib64/libc_nonshared.a  AS_NEEDED ( /lib64/ld-linux-x86-64.so.2 ) )
+	if [[ -n $(host_eprefix) ]] ; then
+		local file
+		grep -lZIF "ld script" "${ED}/$(alt_usrlibdir)"/lib*.{a,so} 2>/dev/null | while read -rd '' file ; do
+			sed -i "s|$(host_eprefix)/|/|g" "${file}" || die
+		done
+	fi
+
+	# We'll take care of the cache ourselves
+	rm -f "${ED}"/etc/ld.so.cache
+
+	# Everything past this point just needs to be done once ...
+	is_final_abi || return 0
+
+	# Make sure the non-native interp can be found on multilib systems even
+	# if the main library set isn't installed into the right place.  Maybe
+	# we should query the active gcc for info instead of hardcoding it ?
+	local i ldso_abi ldso_name
+	local ldso_abi_list=(
+		# x86
+		amd64   /lib64/ld-linux-x86-64.so.2
+		x32     /libx32/ld-linux-x32.so.2
+		x86     /lib/ld-linux.so.2
+		# mips
+		o32     /lib/ld.so.1
+		n32     /lib32/ld.so.1
+		n64     /lib64/ld.so.1
+		# powerpc
+		ppc     /lib/ld.so.1
+		# riscv
+		ilp32d  /lib/ld-linux-riscv32-ilp32d.so.1
+		ilp32   /lib/ld-linux-riscv32-ilp32.so.1
+		lp64d   /lib/ld-linux-riscv64-lp64d.so.1
+		lp64    /lib/ld-linux-riscv64-lp64.so.1
+		# s390
+		s390    /lib/ld.so.1
+		s390x   /lib/ld64.so.1
+		# sparc
+		sparc32 /lib/ld-linux.so.2
+		sparc64 /lib64/ld-linux.so.2
+	)
+	case $(tc-endian) in
+	little)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64.so.1
+			# ELFv2 (glibc does not support ELFv1 on LE)
+			ppc64   /lib64/ld64.so.2
+		)
+		;;
+	big)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64_be.so.1
+			# ELFv1 (glibc does not support ELFv2 on BE)
+			ppc64   /lib64/ld64.so.1
+		)
+		;;
+	esac
+	if [[ ${SYMLINK_LIB} == "yes" ]] && [[ ! -e ${ED}/$(alt_prefix)/lib ]] ; then
+		dosym $(get_abi_LIBDIR ${DEFAULT_ABI}) $(alt_prefix)/lib
+	fi
+	for (( i = 0; i < ${#ldso_abi_list[@]}; i += 2 )) ; do
+		ldso_abi=${ldso_abi_list[i]}
+		has ${ldso_abi} $(get_install_abis) || continue
+
+		ldso_name="$(alt_prefix)${ldso_abi_list[i+1]}"
+		if [[ ! -L ${ED}/${ldso_name} && ! -e ${ED}/${ldso_name} ]] ; then
+			dosym ../$(get_abi_LIBDIR ${ldso_abi})/${ldso_name##*/} ${ldso_name}
+		fi
+	done
+
+	# In the LSB 5.0 definition, someone had the excellent idea to "standardize"
+	# the runtime loader name, see also https://xkcd.com/927/
+	# Normally, in Gentoo one should never come across executables that require this.
+	# However, binary commercial packages are known to adhere to weird practices.
+	# https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-AMD64/LSB-Core-AMD64.html#BASELIB
+	local lsb_ldso_name native_ldso_name lsb_ldso_abi
+	local lsb_ldso_abi_list=(
+		# x86
+		amd64	ld-linux-x86-64.so.2	ld-lsb-x86-64.so.3
+	)
+	for (( i = 0; i < ${#lsb_ldso_abi_list[@]}; i += 3 )) ; do
+		lsb_ldso_abi=${lsb_ldso_abi_list[i]}
+		native_ldso_name=${lsb_ldso_abi_list[i+1]}
+		lsb_ldso_name=${lsb_ldso_abi_list[i+2]}
+		has ${lsb_ldso_abi} $(get_install_abis) || continue
+
+		if [[ ! -L ${ED}/$(get_abi_LIBDIR ${lsb_ldso_abi})/${lsb_ldso_name} && ! -e ${ED}/$(get_abi_LIBDIR ${lsb_ldso_abi})/${lsb_ldso_name} ]] ; then
+			dosym ${native_ldso_name} "$(alt_prefix)/$(get_abi_LIBDIR ${lsb_ldso_abi})/${lsb_ldso_name}"
+		fi
+	done
+
+	# With devpts under Linux mounted properly, we do not need the pt_chown
+	# binary to be setuid.  This is because the default owners/perms will be
+	# exactly what we want.
+	if ! use suid ; then
+		find "${ED}" -name pt_chown -exec chmod -s {} +
+	fi
+
+	#################################################################
+	# EVERYTHING AFTER THIS POINT IS FOR NATIVE GLIBC INSTALLS ONLY #
+	#################################################################
+
+	# Make sure we install some symlink hacks so that when we build
+	# a 2nd stage cross-compiler, gcc finds the target system
+	# headers correctly.  See gcc/doc/gccinstall.info
+	if is_crosscompile ; then
+		# We need to make sure that /lib and /usr/lib always exists.
+		# gcc likes to use relative paths to get to its multilibs like
+		# /usr/lib/../lib64/.  So while we don't install any files into
+		# /usr/lib/, we do need it to exist.
+		keepdir $(alt_prefix)/lib
+		keepdir $(alt_prefix)/usr/lib
+
+		dosym usr/include $(alt_prefix)/sys-include
+		return 0
+	fi
+
+	# Files for Debian-style locale updating
+	dodir /usr/share/i18n
+	sed \
+		-e "/^#/d" \
+		-e "/SUPPORTED-LOCALES=/d" \
+		-e "s: \\\\::g" -e "s:/: :g" \
+		"${S}"/localedata/SUPPORTED > "${ED}"/usr/share/i18n/SUPPORTED \
+		|| die "generating /usr/share/i18n/SUPPORTED failed"
+
+	cd "${S}" || die
+
+	# Install misc network config files
+	insinto /etc
+	doins posix/gai.conf
+
+	if use systemd ; then
+		doins "${WORKDIR}/glibc-systemd-${GLIBC_SYSTEMD_VER}/gentoo-config/nsswitch.conf"
+	else
+		doins nss/nsswitch.conf
+	fi
+
+	# Gentoo-specific
+	newins "${FILESDIR}"/host.conf-1 host.conf
+
+	if use nscd ; then
+		doins nscd/nscd.conf
+
+		newinitd "$(prefixify_ro "${FILESDIR}"/nscd-1)" nscd
+
+		local nscd_args=(
+			-e "s:@PIDFILE@:$(strings "${ED}"/usr/sbin/nscd | grep nscd.pid):"
+		)
+
+		sed -i "${nscd_args[@]}" "${ED}"/etc/init.d/nscd
+
+		use systemd && systemd_dounit nscd/nscd.service
+		newtmpfiles nscd/nscd.tmpfiles nscd.conf
+	fi
+
+	echo 'LDPATH="include ld.so.conf.d/*.conf"' > "${T}"/00glibc
+	doenvd "${T}"/00glibc
+
+	for d in BUGS ChangeLog CONFORMANCE FAQ NEWS NOTES PROJECTS README* ; do
+		[[ -s ${d} ]] && dodoc ${d}
+	done
+	dodoc -r ChangeLog.old
+
+	# Prevent overwriting of the /etc/localtime symlink.  We'll handle the
+	# creation of the "factory" symlink in pkg_postinst().
+	rm -f "${ED}"/etc/localtime
+
+	# Generate all locales if this is a native build as locale generation
+	if use compile-locales && ! is_crosscompile ; then
+		run_locale_gen --inplace-glibc "${ED}/"
+	fi
+}
+
+glibc_headers_install() {
+	local builddir=$(builddir "headers")
+	cd "${builddir}"
+	emake install_root="${D}/$(build_eprefix)$(alt_prefix)" install-headers
+
+	insinto $(alt_headers)/gnu
+	doins "${S}"/include/gnu/stubs.h
+
+	# Make sure we install the sys-include symlink so that when
+	# we build a 2nd stage cross-compiler, gcc finds the target
+	# system headers correctly.  See gcc/doc/gccinstall.info
+	dosym usr/include $(alt_prefix)/sys-include
+}
+
+src_install() {
+	if just_headers ; then
+		export ABI=default
+		glibc_headers_install
+		return
+	fi
+
+	foreach_abi glibc_do_src_install
+
+	if ! use static-libs ; then
+		einfo "Not installing static glibc libraries"
+		find "${ED}" -name "*.a" -and -not -name "*_nonshared.a" -delete
+	fi
+}
+
+# Simple test to make sure our new glibc isn't completely broken.
+# Make sure we don't test with statically built binaries since
+# they will fail.  Also, skip if this glibc is a cross compiler.
+#
+# If coreutils is built with USE=multicall, some of these files
+# will just be wrapper scripts, not actual ELFs we can test.
+glibc_sanity_check() {
+	cd / #228809
+
+	# We enter ${ED} so to avoid trouble if the path contains
+	# special characters; for instance if the path contains the
+	# colon character (:), then the linker will try to split it
+	# and look for the libraries in an unexpected place. This can
+	# lead to unsafe code execution if the generated prefix is
+	# within a world-writable directory.
+	# (e.g. /var/tmp/portage:${HOSTNAME})
+	pushd "${ED}"/$(get_libdir) >/dev/null
+
+	# first let's find the actual dynamic linker here
+	# symlinks may point to the wrong abi
+	local newldso=$(find . -maxdepth 1 -name 'ld*so.?' -type f -print -quit)
+
+	einfo Last-minute run tests with ${newldso} in /$(get_libdir) ...
+
+	local x striptest
+	for x in cal date env free ls true uname uptime ; do
+		x=$(type -p ${x})
+		[[ -z ${x} || ${x} != ${EPREFIX}/* ]] && continue
+		striptest=$(LC_ALL="C" file -L ${x} 2>/dev/null) || continue
+		case ${striptest} in
+		*"statically linked"*) continue;;
+		*"ASCII text"*) continue;;
+		esac
+		# We need to clear the locale settings as the upgrade might want
+		# incompatible locale data.  This test is not for verifying that.
+		LC_ALL=C \
+		${newldso} --library-path . ${x} > /dev/null \
+			|| die "simple run test (${x}) failed"
+	done
+
+	popd >/dev/null
+}
+
+pkg_preinst() {
+	# nothing to do if just installing headers
+	just_headers && return
+
+	einfo "Checking general environment sanity."
+	sanity_prechecks
+
+	# prepare /etc/ld.so.conf.d/ for files
+	mkdir -p "${EROOT}"/etc/ld.so.conf.d
+
+	# Default /etc/hosts.conf:multi to on for systems with small dbs.
+	if [[ $(wc -l < "${EROOT}"/etc/hosts) -lt 1000 ]] ; then
+		sed -i '/^multi off/s:off:on:' "${ED}"/etc/host.conf
+		einfo "Defaulting /etc/host.conf:multi to on"
+	fi
+
+	[[ -n ${ROOT} ]] && return 0
+	[[ -d ${ED}/$(get_libdir) ]] || return 0
+	[[ -z ${BOOTSTRAP_RAP} ]] && glibc_sanity_check
+
+	if [[ -L ${EROOT}/usr/lib/locale ]]; then
+		# Help portage migrate this to a directory
+		# https://bugs.gentoo.org/753740
+		rm "${EROOT}"/usr/lib/locale || die
+	fi
+
+	# Keep around libcrypt so that Perl doesn't break when merging libxcrypt
+	# (libxcrypt is the new provider for now of libcrypt.so.{1,2}).
+	# bug #802207
+	if ! use crypt && has_version "${CATEGORY}/${PN}[crypt]" && ! has preserve-libs ${FEATURES}; then
+		PRESERVED_OLD_LIBCRYPT=1
+		cp -p "${EROOT}/$(get_libdir)/libcrypt$(get_libname 1)" "${T}/libcrypt$(get_libname 1)" || die
+	else
+		PRESERVED_OLD_LIBCRYPT=0
+	fi
+}
+
+glibc_refresh_ldconfig() {
+	if [[ ${MERGE_TYPE} == buildonly ]]; then
+		return
+	fi
+
+	# Version check could be added to avoid unnecessary work, but ldconfig
+	# should finish quickly enough to not matter.
+	ebegin "Refreshing ld.so.cache"
+	ldconfig -i
+	if ! eend $?; then
+		ewarn "Failed to refresh the ld.so.cache for you. Some programs may be broken"
+		ewarn "before you manually do so (ldconfig -i)."
+	fi
+}
+
+pkg_postinst() {
+	# nothing to do if just installing headers
+	just_headers && return
+
+	if ! tc-is-cross-compiler && [[ -x ${EROOT}/usr/sbin/iconvconfig ]] ; then
+		# Generate fastloading iconv module configuration file.
+		"${EROOT}"/usr/sbin/iconvconfig --prefix="${ROOT}/"
+	fi
+
+	if ! is_crosscompile && [[ -z ${ROOT} ]] ; then
+		# glibc-2.38+ on loong has ldconfig support added, but the ELF e_flags
+		# handling has changed as well, which means stale ldconfig auxiliary
+		# cache entries and failure to lookup libgcc_s / libstdc++ (breaking
+		# every C++ application) / libgomp etc., among other breakages.
+		#
+		# To fix this, simply refresh the ld.so.cache without using the
+		# auxiliary cache if we're natively installing on loong. This should
+		# be done relatively soon because we want to minimize the breakage
+		# window for the affected programs.
+		use loong && glibc_refresh_ldconfig
+
+		use compile-locales || run_locale_gen "${EROOT}/"
+	fi
+
+	upgrade_warning
+
+	# Check for sanity of /etc/nsswitch.conf, take 2
+	if [[ -e ${EROOT}/etc/nsswitch.conf ]] && ! has_version sys-auth/libnss-nis ; then
+		local entry
+		for entry in passwd group shadow; do
+			if grep -E -q "^[ \t]*${entry}:.*nis" "${EROOT}"/etc/nsswitch.conf; then
+				ewarn ""
+				ewarn "Your ${EROOT}/etc/nsswitch.conf uses NIS. Support for that has been"
+				ewarn "removed from glibc and is now provided by the package"
+				ewarn "  sys-auth/libnss-nis"
+				ewarn "Install it now to keep your NIS setup working."
+				ewarn ""
+			fi
+		done
+	fi
+
+	if [[ ${PRESERVED_OLD_LIBCRYPT} -eq 1 ]] ; then
+		cp -p "${T}/libcrypt$(get_libname 1)" "${EROOT}/$(get_libdir)/libcrypt$(get_libname 1)" || die
+		preserve_old_lib_notify /$(get_libdir)/libcrypt$(get_libname 1)
+
+		elog "Please ignore a possible later error message about a file collision involving"
+		elog "${EROOT}/$(get_libdir)/libcrypt$(get_libname 1). We need to preserve this file for the moment to keep"
+		elog "the upgrade working, but it also needs to be overwritten when"
+		elog "sys-libs/libxcrypt is installed. See bug 802210 for more details."
+	fi
+}