sys-libs/glibc: Copy unmodified from main tree

Package-Manager: Portage-2.3.64, Repoman-2.3.12
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>

8 files changed, 1856 insertions, 0 deletions

diff --git a/sys-libs/glibc/Manifest b/sys-libs/glibc/Manifest
new file mode 100644
index 0000000..f75ed28
--- /dev/null
+++ b/sys-libs/glibc/Manifest
@@ -0,0 +1,3 @@
+DIST gcc-multilib-bootstrap-20180511.tar.xz 2392908 BLAKE2B f3cf614399368acd8908f60d894c6344a2fa09383b30c1633a0682bc668367c8a2f8c6fec2d41b6e2178d709a2bd8db57e8b2ab56ba263c7d56f819c15acd061 SHA512 98c766e913693ab42ff790557acde2a36a8001e2648046a685b21964200df8d4d52d8452d499c0068c6648284d086ce062c2d36e2c6c2fd8aacd232d193f2853
+DIST glibc-2.29-patches-3.tar.xz 35812 BLAKE2B 90b8bc57b7a63f03617795c368b92e525eccfec462d638dbc25c581e5b7a2a72ffd5191842f5ac443a868cbc950838d7e5120e866d343a14b80c55dcbfa48f30 SHA512 4c9b78d9d1a8aa629418f2d758ef800857780b8a1fd8d3582b88348a513ca26ca7f6ac9110a8c6bae16949b360ba36840d184f42293cd4324760273592d1b438
+DIST glibc-2.29.tar.xz 16515488 BLAKE2B b754e6825176538a2b8ca03fce014f0d87d333dc4d038bf0cda5ee8a2f484cd3ce93ad78ec126737e093ab64b55ceedf04cd08aecb4f8041daaa329e99717afa SHA512 146bc0769fe853d9edbf93cea7f74c5b3d84d69cb7614c62588e7acdecd1ec789a9d8949f3e8b99f8f36f2ccac740a003bed94f32b07817baf780b06cfeb6ed0
diff --git a/sys-libs/glibc/files/2.19/glibc-2.19-hardened-configure-picdefault.patch b/sys-libs/glibc/files/2.19/glibc-2.19-hardened-configure-picdefault.patch
new file mode 100644
index 0000000..341d8c5
--- /dev/null
+++ b/sys-libs/glibc/files/2.19/glibc-2.19-hardened-configure-picdefault.patch
@@ -0,0 +1,30 @@
+Prevent default-fPIE from confusing configure into thinking
+PIC code is default.  This causes glibc to build both PIC and
+non-PIC code as normal, which on the hardened compiler generates
+PIC and PIE.
+
+Patch by Kevin F. Quinn <kevquinn@gentoo.org>
+Fixed for glibc 2.19 by Magnus Granberg <zorry@ume.nu>
+
+--- configure.ac
++++ configure.ac
+@@ -2145,7 +2145,7 @@
+ # error PIC is default.
+ #endif
+ EOF
+-if eval "${CC-cc} -S conftest.c 2>&AS_MESSAGE_LOG_FD 1>&AS_MESSAGE_LOG_FD"; then
++if eval "${CC-cc} -fno-PIE -S conftest.c 2>&AS_MESSAGE_LOG_FD 1>&AS_MESSAGE_LOG_FD"; then
+   libc_cv_pic_default=no
+ fi
+ rm -f conftest.*])
+--- configure
++++ configure
+@@ -7698,7 +7698,7 @@
+ # error PIC is default.
+ #endif
+ EOF
+-if eval "${CC-cc} -S conftest.c 2>&5 1>&5"; then
++if eval "${CC-cc} -fno-PIE -S conftest.c 2>&5 1>&5"; then
+   libc_cv_pic_default=no
+ fi
+ rm -f conftest.*
diff --git a/sys-libs/glibc/files/2.19/glibc-2.19-ia64-gcc-4.8-reloc-hack.patch b/sys-libs/glibc/files/2.19/glibc-2.19-ia64-gcc-4.8-reloc-hack.patch
new file mode 100644
index 0000000..72a616a
--- /dev/null
+++ b/sys-libs/glibc/files/2.19/glibc-2.19-ia64-gcc-4.8-reloc-hack.patch
@@ -0,0 +1,32 @@
+https://bugs.gentoo.org/503838
+http://gcc.gnu.org/PR60465
+https://sourceware.org/ml/libc-alpha/2015-12/msg00556.html
+https://trofi.github.io/posts/189-glibc-on-ia64-or-how-relocations-bootstrap.html
+
+newer versions of gcc generate relocations in the elf_get_dynamic_info func
+which glibc relies on to populate some info structs.  those structs are then
+used by ldso to process relocations in itself.  glibc requires that there are
+no relocations until that point (*after* elf_get_dynamic_info), so we end up
+crashing during elf_get_dynamic_info because the relocation has not yet been
+processed.
+
+this hack shuffles the code in a way that tricks gcc into not generating the
+relocation.  we need to figure out something better for upstream.
+
+--- a/elf/get-dynamic-info.h
++++ b/elf/get-dynamic-info.h
+@@ -66,8 +66,12 @@ elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
+ 	info[DT_VALTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
+ 	     + DT_VERSIONTAGNUM + DT_EXTRANUM] = dyn;
+       else if ((d_tag_utype) DT_ADDRTAGIDX (dyn->d_tag) < DT_ADDRNUM)
+-	info[DT_ADDRTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
+-	     + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM] = dyn;
++	{
++	  d_tag_utype i =
++	      DT_ADDRTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
++	      + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM;
++	  info[i] = dyn;
++	}
+       ++dyn;
+     }
+ 
diff --git a/sys-libs/glibc/files/2.25/glibc-2.25-gentoo-chk_fail.c b/sys-libs/glibc/files/2.25/glibc-2.25-gentoo-chk_fail.c
new file mode 100644
index 0000000..2ef96b7
--- /dev/null
+++ b/sys-libs/glibc/files/2.25/glibc-2.25-gentoo-chk_fail.c
@@ -0,0 +1,303 @@
+/* Copyright (C) 2004-2014 Free Software Foundation, Inc.
+   Copyright (C) 2006-2014 Gentoo Foundation Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+/* Hardened Gentoo SSP and FORTIFY handler
+
+   A failure handler that does not use functions from the rest of glibc;
+   it uses the INTERNAL_SYSCALL methods directly.  This helps ensure no
+   possibility of recursion into the handler.
+
+   Direct all bug reports to http://bugs.gentoo.org/
+
+   People who have contributed significantly to the evolution of this file:
+   Ned Ludd - <solar[@]gentoo.org>
+   Alexander Gabert - <pappy[@]gentoo.org>
+   The PaX Team - <pageexec[@]freemail.hu>
+   Peter S. Mazinger - <ps.m[@]gmx.net>
+   Yoann Vandoorselaere - <yoann[@]prelude-ids.org>
+   Robert Connolly - <robert[@]linuxfromscratch.org>
+   Cory Visi <cory[@]visi.name>
+   Mike Frysinger <vapier[@]gentoo.org>
+   Magnus Granberg <zorry[@]gentoo.org>
+   Kevin F. Quinn - <kevquinn[@]gentoo.org>
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include <sys/types.h>
+
+#include <sysdep-cancel.h>
+#include <sys/syscall.h>
+
+#include <kernel-features.h>
+
+#include <alloca.h>
+/* from sysdeps */
+#include <socketcall.h>
+/* for the stuff in bits/socket.h */
+#include <sys/socket.h>
+#include <sys/un.h>
+
+/* Sanity check on SYSCALL macro names - force compilation
+ * failure if the names used here do not exist
+ */
+#if !defined __NR_socketcall && !defined __NR_socket
+# error Cannot do syscall socket or socketcall
+#endif
+#if !defined __NR_socketcall && !defined __NR_connect
+# error Cannot do syscall connect or socketcall
+#endif
+#ifndef __NR_write
+# error Cannot do syscall write
+#endif
+#ifndef __NR_close
+# error Cannot do syscall close
+#endif
+#ifndef __NR_getpid
+# error Cannot do syscall getpid
+#endif
+#ifndef __NR_kill
+# error Cannot do syscall kill
+#endif
+#ifndef __NR_exit
+# error Cannot do syscall exit
+#endif
+#ifdef SSP_SMASH_DUMPS_CORE
+# define ENABLE_SSP_SMASH_DUMPS_CORE 1
+# if !defined _KERNEL_NSIG && !defined _NSIG
+#  error No _NSIG or _KERNEL_NSIG for rt_sigaction
+# endif
+# if !defined __NR_sigaction && !defined __NR_rt_sigaction
+#  error Cannot do syscall sigaction or rt_sigaction
+# endif
+/* Although rt_sigaction expects sizeof(sigset_t) - it expects the size
+ * of the _kernel_ sigset_t which is not the same as the user sigset_t.
+ * Most arches have this as _NSIG bits - mips has _KERNEL_NSIG bits for
+ * some reason.
+ */
+# ifdef _KERNEL_NSIG
+#  define _SSP_NSIG _KERNEL_NSIG
+# else
+#  define _SSP_NSIG _NSIG
+# endif
+#else
+# define _SSP_NSIG 0
+# define ENABLE_SSP_SMASH_DUMPS_CORE 0
+#endif
+
+/* Define DO_SIGACTION - default to newer rt signal interface but
+ * fallback to old as needed.
+ */
+#ifdef __NR_rt_sigaction
+# define DO_SIGACTION(signum, act, oldact) \
+	INLINE_SYSCALL(rt_sigaction, 4, signum, act, oldact, _SSP_NSIG/8)
+#else
+# define DO_SIGACTION(signum, act, oldact) \
+	INLINE_SYSCALL(sigaction, 3, signum, act, oldact)
+#endif
+
+/* Define DO_SOCKET/DO_CONNECT functions to deal with socketcall vs socket/connect */
+#if defined(__NR_socket) && defined(__NR_connect)
+# define USE_OLD_SOCKETCALL 0
+#else
+# define USE_OLD_SOCKETCALL 1
+#endif
+
+/* stub out the __NR_'s so we can let gcc optimize away dead code */
+#ifndef __NR_socketcall
+# define __NR_socketcall 0
+#endif
+#ifndef __NR_socket
+# define __NR_socket 0
+#endif
+#ifndef __NR_connect
+# define __NR_connect 0
+#endif
+#define DO_SOCKET(result, domain, type, protocol) \
+	do { \
+		if (USE_OLD_SOCKETCALL) { \
+			socketargs[0] = domain; \
+			socketargs[1] = type; \
+			socketargs[2] = protocol; \
+			socketargs[3] = 0; \
+			result = INLINE_SYSCALL(socketcall, 2, SOCKOP_socket, socketargs); \
+		} else \
+			result = INLINE_SYSCALL(socket, 3, domain, type, protocol); \
+	} while (0)
+#define DO_CONNECT(result, sockfd, serv_addr, addrlen) \
+	do { \
+		if (USE_OLD_SOCKETCALL) { \
+			socketargs[0] = sockfd; \
+			socketargs[1] = (unsigned long int)serv_addr; \
+			socketargs[2] = addrlen; \
+			socketargs[3] = 0; \
+			result = INLINE_SYSCALL(socketcall, 2, SOCKOP_connect, socketargs); \
+		} else \
+			result = INLINE_SYSCALL(connect, 3, sockfd, serv_addr, addrlen); \
+	} while (0)
+
+#ifndef _PATH_LOG
+# define _PATH_LOG "/dev/log"
+#endif
+
+static const char path_log[] = _PATH_LOG;
+
+/* For building glibc with SSP switched on, define __progname to a
+ * constant if building for the run-time loader, to avoid pulling
+ * in more of libc.so into ld.so
+ */
+#ifdef IS_IN_rtld
+static const char *__progname = "<ldso>";
+#else
+extern const char *__progname;
+#endif
+
+#ifdef GENTOO_SSP_HANDLER
+# define ERROR_MSG "stack smashing"
+#else
+# define ERROR_MSG "buffer overflow"
+#endif
+
+/* Common handler code, used by chk_fail
+ * Inlined to ensure no self-references to the handler within itself.
+ * Data static to avoid putting more than necessary on the stack,
+ * to aid core debugging.
+ */
+__attribute__ ((__noreturn__, __always_inline__))
+static inline void
+__hardened_gentoo_fail(void)
+{
+#define MESSAGE_BUFSIZ 512
+	static pid_t pid;
+	static int plen, i, hlen;
+	static char message[MESSAGE_BUFSIZ];
+	/* <11> is LOG_USER|LOG_ERR. A dummy date for loggers to skip over. */
+	static const char msg_header[] = "<11>" __DATE__ " " __TIME__ " glibc-gentoo-hardened-check: ";
+	static const char msg_ssd[] = "*** " ERROR_MSG " detected ***: ";
+	static const char msg_terminated[] = " terminated; ";
+	static const char msg_report[] = "report to " REPORT_BUGS_TO "\n";
+	static const char msg_unknown[] = "<unknown>";
+	static int log_socket, connect_result;
+	static struct sockaddr_un sock;
+	static unsigned long int socketargs[4];
+
+	/* Build socket address */
+	sock.sun_family = AF_UNIX;
+	i = 0;
+	while (path_log[i] != '\0' && i < sizeof(sock.sun_path) - 1) {
+		sock.sun_path[i] = path_log[i];
+		++i;
+	}
+	sock.sun_path[i] = '\0';
+
+	/* Try SOCK_DGRAM connection to syslog */
+	connect_result = -1;
+	DO_SOCKET(log_socket, AF_UNIX, SOCK_DGRAM, 0);
+	if (log_socket != -1)
+		DO_CONNECT(connect_result, log_socket, &sock, sizeof(sock));
+	if (connect_result == -1) {
+		if (log_socket != -1)
+			INLINE_SYSCALL(close, 1, log_socket);
+		/* Try SOCK_STREAM connection to syslog */
+		DO_SOCKET(log_socket, AF_UNIX, SOCK_STREAM, 0);
+		if (log_socket != -1)
+			DO_CONNECT(connect_result, log_socket, &sock, sizeof(sock));
+	}
+
+	/* Build message.  Messages are generated both in the old style and new style,
+	 * so that log watchers that are configured for the old-style message continue
+	 * to work.
+	 */
+#define strconcat(str) \
+	({ \
+		i = 0; \
+		while ((str[i] != '\0') && ((i + plen) < (MESSAGE_BUFSIZ - 1))) { \
+			message[plen + i] = str[i]; \
+			++i; \
+		} \
+		plen += i; \
+	})
+
+	/* Tersely log the failure */
+	plen = 0;
+	strconcat(msg_header);
+	hlen = plen;
+	strconcat(msg_ssd);
+	if (__progname != NULL)
+		strconcat(__progname);
+	else
+		strconcat(msg_unknown);
+	strconcat(msg_terminated);
+	strconcat(msg_report);
+
+	/* Write out error message to STDERR, to syslog if open */
+	INLINE_SYSCALL(write, 3, STDERR_FILENO, message + hlen, plen - hlen);
+	if (connect_result != -1) {
+		INLINE_SYSCALL(write, 3, log_socket, message, plen);
+		INLINE_SYSCALL(close, 1, log_socket);
+	}
+
+	/* Time to kill self since we have no idea what is going on */
+	pid = INLINE_SYSCALL(getpid, 0);
+
+	if (ENABLE_SSP_SMASH_DUMPS_CORE) {
+		/* Remove any user-supplied handler for SIGABRT, before using it. */
+#if 0
+		/*
+		 * Note: Disabled because some programs catch & process their
+		 * own crashes.  We've already enabled this code path which
+		 * means we want to let core dumps happen.
+		 */
+		static struct sigaction default_abort_act;
+		default_abort_act.sa_handler = SIG_DFL;
+		default_abort_act.sa_sigaction = NULL;
+		__sigfillset(&default_abort_act.sa_mask);
+		default_abort_act.sa_flags = 0;
+		if (DO_SIGACTION(SIGABRT, &default_abort_act, NULL) == 0)
+#endif
+			INLINE_SYSCALL(kill, 2, pid, SIGABRT);
+	}
+
+	/* SIGKILL is only signal which cannot be caught */
+	INLINE_SYSCALL(kill, 2, pid, SIGKILL);
+
+	/* In case the kill didn't work, exit anyway.
+	 * The loop prevents gcc thinking this routine returns.
+	 */
+	while (1)
+		INLINE_SYSCALL(exit, 1, 137);
+}
+
+__attribute__ ((__noreturn__))
+#ifdef GENTOO_SSP_HANDLER
+void __stack_chk_fail(void)
+#else
+void __chk_fail(void)
+#endif
+{
+	__hardened_gentoo_fail();
+}
+
+#ifdef GENTOO_SSP_HANDLER
+strong_alias (__stack_chk_fail, __stack_chk_fail_local)
+#endif
diff --git a/sys-libs/glibc/files/nscd.service b/sys-libs/glibc/files/nscd.service
new file mode 100644
index 0000000..25a3b1d
--- /dev/null
+++ b/sys-libs/glibc/files/nscd.service
@@ -0,0 +1,15 @@
+[Unit]
+Description=Name Service Cache Daemon
+After=network.target
+
+[Service]
+ExecStart=/usr/sbin/nscd -F
+ExecStop=/usr/sbin/nscd --shutdown
+ExecReload=/usr/sbin/nscd -i passwd
+ExecReload=/usr/sbin/nscd -i group
+ExecReload=/usr/sbin/nscd -i hosts
+ExecReload=/usr/sbin/nscd -i services
+Restart=always
+
+[Install]
+WantedBy=multi-user.target
diff --git a/sys-libs/glibc/files/nscd.tmpfilesd b/sys-libs/glibc/files/nscd.tmpfilesd
new file mode 100644
index 0000000..52edbba
--- /dev/null
+++ b/sys-libs/glibc/files/nscd.tmpfilesd
@@ -0,0 +1,4 @@
+# Configuration to create /run/nscd directory
+# Used as part of systemd's tmpfiles
+
+d /run/nscd 0755 root root
diff --git a/sys-libs/glibc/glibc-2.29-r2.ebuild b/sys-libs/glibc/glibc-2.29-r2.ebuild
new file mode 100644
index 0000000..60641cf
--- /dev/null
+++ b/sys-libs/glibc/glibc-2.29-r2.ebuild
@@ -0,0 +1,1448 @@
+# Copyright 1999-2019 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=6
+
+PYTHON_COMPAT=( python3_{5,6,7} )
+
+inherit python-any-r1 prefix eutils eapi7-ver toolchain-funcs flag-o-matic gnuconfig \
+	multilib systemd multiprocessing
+
+DESCRIPTION="GNU libc C library"
+HOMEPAGE="https://www.gnu.org/software/libc/"
+LICENSE="LGPL-2.1+ BSD HPND ISC inner-net rc PCRE"
+RESTRICT="strip" # Strip ourself #46186
+SLOT="2.2"
+
+EMULTILIB_PKG="true"
+
+if [[ ${PV} == 9999* ]]; then
+	EGIT_REPO_URI="https://sourceware.org/git/glibc.git"
+	inherit git-r3
+else
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~m68k ~mips ~ppc ~ppc64 ~s390 ~sh ~sparc ~x86"
+	SRC_URI="mirror://gnu/glibc/${P}.tar.xz"
+fi
+
+RELEASE_VER=${PV}
+
+GCC_BOOTSTRAP_VER=20180511
+
+# Gentoo patchset
+PATCH_VER=3
+
+SRC_URI+=" https://dev.gentoo.org/~dilfridge/distfiles/${P}-patches-${PATCH_VER}.tar.xz"
+SRC_URI+=" multilib? ( https://dev.gentoo.org/~dilfridge/distfiles/gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz )"
+
+IUSE="audit caps cet compile-locales doc gd headers-only +multiarch multilib nscd profile selinux +ssp suid systemtap test vanilla"
+
+# Minimum kernel version that glibc requires
+MIN_KERN_VER="3.2.0"
+
+# 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
+
+# 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.
+COMMON_DEPEND="
+	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}
+	${PYTHON_DEPS}
+	>=app-misc/pax-utils-0.1.10
+	sys-devel/bison
+	!<sys-apps/sandbox-1.6
+	!<sys-apps/portage-2.1.2
+	!<sys-devel/bison-2.7
+	!<sys-devel/make-4
+	doc? ( sys-apps/texinfo )
+	test? ( >=net-dns/libidn2-2.0.5 )
+"
+RDEPEND="${COMMON_DEPEND}
+	sys-apps/gentoo-functions
+	!sys-kernel/ps3-sources
+	!sys-libs/nss-db
+"
+
+if [[ ${CATEGORY} == cross-* ]] ; then
+	DEPEND+=" !headers-only? (
+		>=${CATEGORY}/binutils-2.24
+		>=${CATEGORY}/gcc-6
+	)"
+	[[ ${CATEGORY} == *-linux* ]] && DEPEND+=" ${CATEGORY}/linux-headers"
+else
+	DEPEND+="
+		>=sys-devel/binutils-2.24
+		>=sys-devel/gcc-6
+		virtual/os-headers
+	"
+	RDEPEND+="
+		>=net-dns/libidn2-2.0.5
+		vanilla? ( !sys-libs/timezone-data )
+	"
+	PDEPEND+=" !vanilla? ( sys-libs/timezone-data )"
+fi
+
+#
+# Small helper functions
+#
+
+is_crosscompile() {
+	[[ ${CHOST} != ${CTARGET} ]]
+}
+
+just_headers() {
+	is_crosscompile && use headers-only
+}
+
+alt_prefix() {
+	is_crosscompile && echo /usr/${CTARGET}
+}
+
+# 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 ${ALT_BUILD_HEADERS} ]] ; then
+		ALT_BUILD_HEADERS="${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' "$*" > glibc-test.c
+
+	nonfatal emake -s glibc-test
+	ret=$?
+
+	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 $(tc-arch) in
+		x86)
+			# -march needed for #185404 #199334
+			# TODO: When creating the first glibc cross-compile, this test will
+			# always fail as it does a full link which in turn requires glibc.
+			# Probably also applies when changing multilib profile settings (e.g.
+			# enabling x86 when the profile was amd64-only previously).
+			# We could change main to _start and pass -nostdlib here so that we
+			# only test the gcc code compilation.  Or we could do a compile and
+			# then look for the symbol via scanelf.
+			if ! do_compile_test "" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n' 2>/dev/null ; then
+				local t=${CTARGET_OPT:-${CTARGET}}
+				t=${t%%-*}
+				filter-flags '-march=*'
+				export CFLAGS="-march=${t} ${CFLAGS}"
+				einfo "Auto adding -march=${t} to CFLAGS #185404"
+			fi
+		;;
+		amd64)
+			# -march needed for #185404 #199334
+			# Note: This test only matters when the x86 ABI is enabled, so we could
+			# optimize a bit and elide it.
+			# TODO: See cross-compile issues listed above for x86.
+			if ! do_compile_test "${CFLAGS_x86}" 'void f(int i, void *p) {if (__sync_fetch_and_add(&i, 1)) f(i, p);}\nint main(){return 0;}\n' 2>/dev/null ; then
+				local t=${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"
+			fi
+		;;
+		mips)
+			# The mips abi cannot support the GNU style hashes. #233233
+			filter-ldflags -Wl,--hash-style=gnu -Wl,--hash-style=both
+		;;
+		sparc)
+			# Both sparc and sparc64 can use -fcall-used-g6.  -g7 is bad, though.
+			filter-flags "-fcall-used-g7"
+			append-flags "-fcall-used-g6"
+
+			# If the CHOST is the basic one (e.g. not sparcv9-xxx already),
+			# try to pick a better one so glibc can use cpu-specific .S files.
+			# We key off the CFLAGS to get a good value.  Also need to handle
+			# version skew.
+			# We can't force users to set their CHOST to their exact machine
+			# as many of these are not recognized by config.sub/gcc and such :(.
+			# Note: If the mcpu values don't scale, we might try probing CPP defines.
+			# Note: Should we factor in -Wa,-AvXXX flags too ?  Or -mvis/etc... ?
+
+			local cpu
+			case ${CTARGET} in
+			sparc64-*)
+				case $(get-flag mcpu) in
+				niagara[234])
+					if ver_test -ge 2.8 ; then
+						cpu="sparc64v2"
+					elif ver_test -ge 2.4 ; then
+						cpu="sparc64v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparc64b"
+					fi
+					;;
+				niagara)
+					if ver_test -ge 2.4 ; then
+						cpu="sparc64v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparc64b"
+					fi
+					;;
+				ultrasparc3)
+					cpu="sparc64b"
+					;;
+				*)
+					# 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
+					[[ -z ${cpu} ]] && append-flags "-Wa,-xarch=v9a"
+					;;
+				esac
+				;;
+			sparc-*)
+				case $(get-flag mcpu) in
+				niagara[234])
+					if ver_test -ge 2.8 ; then
+						cpu="sparcv9v2"
+					elif ver_test -ge 2.4 ; then
+						cpu="sparcv9v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparcv9b"
+					else
+						cpu="sparcv9"
+					fi
+					;;
+				niagara)
+					if ver_test -ge 2.4 ; then
+						cpu="sparcv9v"
+					elif ver_test -ge 2.2.3 ; then
+						cpu="sparcv9b"
+					else
+						cpu="sparcv9"
+					fi
+					;;
+				ultrasparc3)
+					cpu="sparcv9b"
+					;;
+				v9|ultrasparc)
+					cpu="sparcv9"
+					;;
+				v8|supersparc|hypersparc|leon|leon3)
+					cpu="sparcv8"
+					;;
+				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=${ASFLAGS_BASE}
+
+	# Over-zealous CFLAGS can often cause problems.  What may work for one
+	# person may not work for another.  To avoid a large influx of bugs
+	# relating to failed builds, we strip most CFLAGS out to ensure as few
+	# problems as possible.
+	strip-flags
+	strip-unsupported-flags
+	filter-flags -m32 -m64 '-mabi=*'
+
+	# glibc aborts if rpath is set by LDFLAGS
+	filter-ldflags '-Wl,-rpath=*'
+
+	# #492892
+	filter-flags -frecord-gcc-switches
+
+	unset CBUILD_OPT CTARGET_OPT
+	if use multilib ; then
+		CTARGET_OPT=$(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
+
+	# Lock glibc at -O2; we want to be conservative here.
+	# -fno-strict-aliasing is to work around #155906.
+	filter-flags '-O?'
+	append-flags -O2 -fno-strict-aliasing
+
+	filter-flags '-fstack-protector*'
+}
+
+want_tls() {
+	# Archs that can use TLS (Thread Local Storage)
+	case $(tc-arch) in
+		x86)
+			# requires i486 or better #106556
+			[[ ${CTARGET} == i[4567]86* ]] && return 0
+			return 1
+		;;
+	esac
+	return 0
+}
+
+want__thread() {
+	want_tls || return 1
+
+	# For some reason --with-tls --with__thread is causing segfaults on sparc32.
+	[[ ${PROFILE_ARCH} == "sparc" ]] && return 1
+
+	[[ -n ${WANT__THREAD} ]] && return ${WANT__THREAD}
+
+	# only test gcc -- can't test linking yet
+	tc-has-tls -c ${CTARGET}
+	WANT__THREAD=$?
+
+	return ${WANT__THREAD}
+}
+
+use_multiarch() {
+	# Allow user to disable runtime arch detection in multilib.
+	use multiarch || return 1
+	# Make sure binutils is new enough to support indirect functions,
+	# #336792. This funky sed supports gold and bfd linkers.
+	local bver nver
+	bver=$($(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
+	local VAR=CFLAGS_${ABI}
+	# 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.
+	: ${__GLIBC_CC:=$(tc-getCC ${CTARGET_OPT:-${CTARGET}})}
+	export __GLIBC_CC CC="${__GLIBC_CC} ${!VAR}"
+	einfo " $(printf '%15s' 'Manual CC:')   ${CC}"
+}
+
+foreach_abi() {
+	setup_env
+
+	local ret=0
+	local abilist=""
+	if use multilib ; then
+		abilist=$(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 ${PATCH_VER} ]] && ! use vanilla && b+=" p${PATCH_VER}"
+	echo "${b}"
+}
+
+check_devpts() {
+	# Make sure devpts is mounted correctly for use w/out setuid pt_chown.
+
+	# If merely building the binary package, then there's nothing to verify.
+	[[ ${MERGE_TYPE} == "buildonly" ]] && return
+
+	# Only sanity check when installing the native glibc.
+	[[ ${ROOT} != "/" ]] && return
+
+	# If they're opting in to the old suid code, then no need to check.
+	use suid && return
+
+	if awk '$3 == "devpts" && $4 ~ /[, ]gid=5[, ]/ { exit 1 }' /proc/mounts ; then
+		eerror "In order to use glibc with USE=-suid, you must make sure that"
+		eerror "you have devpts mounted at /dev/pts with the gid=5 option."
+		eerror "Openrc should do this for you, so you should check /etc/fstab"
+		eerror "and make sure you do not have any invalid settings there."
+		die "mount & fix your /dev/pts settings"
+	fi
+}
+
+# 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 ${CTARGET}) -I "${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() {
+	# Make sure devpts is mounted correctly for use w/out setuid pt_chown
+	check_devpts
+
+	# Prevent native builds from downgrading
+	if [[ ${MERGE_TYPE} != "buildonly" ]] && \
+	   [[ ${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."
+			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
+
+	# Users have had a chance to phase themselves, time to give em the boot
+	if [[ -e ${EROOT}/etc/locale.gen ]] && [[ -e ${EROOT}/etc/locales.build ]] ; then
+		eerror "You still haven't deleted ${EROOT}/etc/locales.build."
+		eerror "Do so now after making sure ${EROOT}/etc/locale.gen is kosher."
+		die "Lazy upgrader detected"
+	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
+
+	# Check for sanity of /etc/nsswitch.conf
+	if [[ -e ${EROOT}/etc/nsswitch.conf ]] ; then
+		local entry
+		for entry in passwd group shadow; do
+			if ! egrep -q "^[ \t]*${entry}:.*files" "${EROOT}"/etc/nsswitch.conf; then
+				eerror "Your ${EROOT}/etc/nsswitch.conf is out of date."
+				eerror "Please make sure you have 'files' entries for"
+				eerror "'passwd:', 'group:' and 'shadow:' databases."
+				eerror "For more details see:"
+				eerror "  https://wiki.gentoo.org/wiki/Project:Toolchain/nsswitch.conf_in_glibc-2.26"
+				die "nsswitch.conf has no 'files' provider in '${entry}'."
+			fi
+		done
+	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 ; then
+		ebegin "Checking gcc for __thread support"
+		if ! eend $(want__thread ; echo $?) ; then
+			echo
+			eerror "Could not find a gcc that supports the __thread directive!"
+			eerror "Please update your binutils/gcc and try again."
+			die "No __thread support in gcc!"
+		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 ${want_kv}!"
+					die "Kernel version too low!"
+				fi
+			fi
+
+			ebegin "Checking linux-headers version (${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
+}
+
+#
+# the phases
+#
+
+# pkg_pretend
+
+pkg_pretend() {
+	# All the checks...
+	einfo "Checking general environment sanity."
+	sanity_prechecks
+}
+
+pkg_setup() {
+	# see bug 682570
+	[[ -z ${BOOTSTRAP_RAP} ]] && python-any-r1_pkg_setup
+}
+
+# src_unpack
+
+src_unpack() {
+	# Consistency is not guaranteed between pkg_ and src_ ...
+	sanity_prechecks
+
+	use multilib && unpack gcc-multilib-bootstrap-${GCC_BOOTSTRAP_VER}.tar.xz
+
+	setup_env
+
+	if [[ -n ${EGIT_REPO_URI} ]] ; then
+		git-r3_src_unpack
+	else
+		unpack ${P}.tar.xz
+	fi
+
+	cd "${WORKDIR}" || die
+	unpack glibc-${RELEASE_VER}-patches-${PATCH_VER}.tar.xz
+}
+
+src_prepare() {
+	if ! use vanilla ; then
+		elog "Applying Gentoo Glibc Patchset ${RELEASE_VER}-${PATCH_VER}"
+		eapply "${WORKDIR}"/patches
+		einfo "Done."
+	fi
+
+	default
+
+	gnuconfig_update
+
+	cd "${WORKDIR}"
+	find . -name configure -exec touch {} +
+
+	eprefixify extra/locale/locale-gen
+
+	# Fix permissions on some of the scripts.
+	chmod u+x "${S}"/scripts/*.sh
+
+	cd "${S}"
+}
+
+glibc_do_configure() {
+	# Glibc does not work with gold (for various reasons) #269274.
+	tc-ld-disable-gold
+
+	# CXX isnt handled by the multilib system, so if we dont unset here
+	# we accumulate crap across abis
+	unset CXX
+
+	einfo "Configuring glibc for nptl"
+
+	if use doc ; then
+		export MAKEINFO=makeinfo
+	else
+		export MAKEINFO=/dev/null
+	fi
+
+	local v
+	for v in ABI CBUILD CHOST CTARGET CBUILD_OPT CTARGET_OPT CC CXX LD {AS,C,CPP,CXX,LD}FLAGS MAKEINFO ; do
+		einfo " $(printf '%15s' ${v}:)   ${!v}"
+	done
+
+	# CFLAGS can contain ABI-specific flags like -mfpu=neon, see bug #657760
+	# To build .S (assembly) files with the same ABI-specific flags
+	# upstream currently recommends adding CFLAGS to CC/CXX:
+	#    https://sourceware.org/PR23273
+	# Note: Passing CFLAGS via CPPFLAGS overrides glibc's arch-specific CFLAGS
+	# and breaks multiarch support. See 659030#c3 for an example.
+	# The glibc configure script doesn't properly use LDFLAGS all the time.
+	export CC="$(tc-getCC ${CTARGET}) ${CFLAGS} ${LDFLAGS}"
+	einfo " $(printf '%15s' 'Manual CC:')   ${CC}"
+
+	# Some of the tests are written in C++, so we need to force our multlib abis in, bug 623548
+	export CXX="$(tc-getCXX ${CTARGET}) $(get_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
+	einfo " $(printf '%15s' 'Manual CXX:')   ${CXX}"
+
+	echo
+
+	local myconf=()
+
+	case ${CTARGET} in
+		m68k*)
+			# setjmp() is not compatible with stack protection:
+			# https://sourceware.org/PR24202
+			myconf+=( --enable-stack-protector=no )
+			;;
+		powerpc-*)
+			# Currently gcc on powerpc32 generates invalid code for
+			# __builtin_return_address(0) calls. Normally programs
+			# don't do that but malloc hooks in glibc do:
+			# https://gcc.gnu.org/PR81996
+			# https://bugs.gentoo.org/629054
+			myconf+=( --enable-stack-protector=no )
+			;;
+		*)
+			myconf+=( --enable-stack-protector=$(usex ssp all no) )
+			;;
+	esac
+	myconf+=( --enable-stackguard-randomization )
+
+	# 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) ;;
+		# 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+=(
+		--without-cvs
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		$(use_enable profile)
+		$(use_with gd)
+		--with-headers=$(alt_build_headers)
+		--prefix="${EPREFIX}/usr"
+		--sysconfdir="${EPREFIX}/etc"
+		--localstatedir="${EPREFIX}/var"
+		--libdir='$(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_multiarch || echo --disable-multi-arch)
+		$(use_enable systemtap)
+		$(use_enable nscd)
+		${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=$(usex caps || echo no)
+
+	# There is no configure option for this and we need to export it
+	# since the glibc build will re-run configure on itself
+	export libc_cv_rootsbindir="${EPREFIX}/sbin"
+	export libc_cv_slibdir="${EPREFIX}/$(get_libdir)"
+
+	# We take care of patching our binutils to use both hash styles,
+	# and many people like to force gnu hash style only, so disable
+	# this overriding check.  #347761
+	export libc_cv_hashstyle=no
+
+	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 ${GCC_BOOTSTRAP_VER} ]] && use multilib ; then
+		echo 'main(){}' > "${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 ${CTARGET} in
+	riscv*)
+		# RISC-V interrogates the compiler to determine which target to
+		# build.  If building the headers then we don't strictly need a
+		# RISC-V compiler, so the built-in definitions that are provided
+		# along with all RISC-V compiler might not exist.  This causes
+		# glibc's RISC-V preconfigure script to blow up.  Since we're just
+		# building the headers any value will actually work here, so just
+		# pick the standard one (rv64g/lp64d) to make the build scripts
+		# happy for now -- the headers are all the same anyway so it
+		# doesn't matter.
+		headers_only_arch_CPPFLAGS+=(
+			-D__riscv_xlen=64
+			-D__riscv_flen=64
+			-D__riscv_float_abi_double=1
+			-D__riscv_atomic=1
+		) ;;
+	esac
+
+	local myconf=()
+	myconf+=(
+		--disable-sanity-checks
+		--enable-hacker-mode
+		--without-cvs
+		--disable-werror
+		--enable-bind-now
+		--build=${CBUILD_OPT:-${CBUILD}}
+		--host=${CTARGET_OPT:-${CTARGET}}
+		--with-headers=$(alt_build_headers)
+		--prefix="${EPREFIX}/usr"
+		${EXTRA_ECONF}
+	)
+
+	# Nothing is compiled here which would affect the headers for the target.
+	# So forcing CC/CFLAGS is sane.
+	local headers_only_CC=$(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
+}
+
+do_src_compile() {
+	emake -C "$(builddir nptl)" || die "make nptl for ${ABI} failed"
+}
+
+src_compile() {
+	if just_headers ; then
+		return
+	fi
+
+	foreach_abi do_src_compile
+}
+
+glibc_src_test() {
+	cd "$(builddir nptl)"
+	emake check
+}
+
+do_src_test() {
+	local ret=0
+
+	glibc_src_test
+	: $(( ret |= $? ))
+
+	return ${ret}
+}
+
+src_test() {
+	if just_headers ; then
+		return
+	fi
+
+	# Give tests more time to complete.
+	export TIMEOUTFACTOR=5
+
+	foreach_abi do_src_test || die "tests failed"
+}
+
+run_locale_gen() {
+	# if the host locales.gen contains no entries, we'll install everything
+	local root="$1"
+	local locale_list="${root}/etc/locale.gen"
+	if [[ -z $(locale-gen --list --config "${locale_list}") ]] ; then
+		ewarn "Generating all locales; edit /etc/locale.gen to save time/space"
+		locale_list="${root}/usr/share/i18n/SUPPORTED"
+	fi
+
+	locale-gen --jobs $(makeopts_jobs) --config "${locale_list}" \
+		--destdir "${root}"
+}
+
+glibc_do_src_install() {
+	local builddir=$(builddir nptl)
+	cd "${builddir}"
+
+	emake install_root="${D}$(alt_prefix)" install || die
+
+	# This version (2.26) provides some compatibility libraries for the NIS/NIS+ support
+	# which come without headers etc. Only needed for binary packages since the
+	# external net-libs/libnsl has increased soversion. Keep only versioned libraries.
+	find "${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)
+
+	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-${upstream_pv}.a || die
+	fi
+
+	# We'll take care of the cache ourselves
+	rm -f "${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
+		ppc64   /lib64/ld64.so.1
+		# riscv
+		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
+		)
+		;;
+	big)
+		ldso_abi_list+=(
+			# arm
+			arm64   /lib/ld-linux-aarch64_be.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##*/} ${ldso_name}
+		fi
+	done
+
+	# With devpts under Linux mounted properly, we do not need the pt_chown
+	# binary to be setuid.  This is because the default owners/perms will be
+	# exactly what we want.
+	if ! use suid ; then
+		find "${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 > "${ED}"/usr/share/i18n/SUPPORTED \
+		|| die "generating /usr/share/i18n/SUPPORTED failed"
+	cd "${WORKDIR}"/extra/locale
+	dosbin locale-gen
+	doman *.[0-8]
+	insinto /etc
+	doins locale.gen
+
+	# Make sure all the ABI's can find the locales and so we only
+	# have to generate one set
+	local a
+	keepdir /usr/$(get_libdir)/locale
+	for a in $(get_install_abis) ; do
+		if [[ ! -e ${ED}/usr/$(get_abi_LIBDIR ${a})/locale ]] ; then
+			dosym ../$(get_libdir)/locale /usr/$(get_abi_LIBDIR ${a})/locale
+		fi
+	done
+
+	# HACK: If we're building for riscv, we need to additionally make sure that
+	# we can find the locale archive afterwards
+	case ${CTARGET} in
+		riscv*)
+			if [[ ! -e ${ED}/usr/lib/locale ]] ; then
+				dosym ../$(get_libdir)/locale /usr/lib/locale
+			fi
+			;;
+		*) ;;
+	esac
+
+	cd "${S}"
+
+	# Install misc network config files
+	insinto /etc
+	doins nscd/nscd.conf posix/gai.conf nss/nsswitch.conf
+	doins "${WORKDIR}"/extra/etc/*.conf
+
+	if use nscd ; then
+		doinitd "$(prefixify_ro "${WORKDIR}"/extra/etc/nscd)"
+
+		local nscd_args=(
+			-e "s:@PIDFILE@:$(strings "${ED}"/usr/sbin/nscd | grep nscd.pid):"
+		)
+
+		sed -i "${nscd_args[@]}" "${ED}"/etc/init.d/nscd
+
+		systemd_dounit nscd/nscd.service
+		systemd_newtmpfilesd nscd/nscd.tmpfiles nscd.conf
+	else
+		# Do this since extra/etc/*.conf above might have nscd.conf.
+		rm -f "${ED}"/etc/nscd.conf
+	fi
+
+	echo 'LDPATH="include ld.so.conf.d/*.conf"' > "${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 "${ED}"
+	fi
+}
+
+glibc_headers_install() {
+	local builddir=$(builddir "headers")
+	cd "${builddir}"
+	emake install_root="${D}$(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 $(alt_prefix)/sys-include
+}
+
+src_strip() {
+	# gdb is lame and requires some debugging information to remain in
+	# libpthread, so we need to strip it by hand.  libthread_db makes no
+	# sense stripped as it is only used when debugging.
+	local pthread=$(has splitdebug ${FEATURES} && echo "libthread_db" || echo "lib{pthread,thread_db}")
+	env \
+		-uRESTRICT \
+		CHOST=${CTARGET} \
+		STRIP_MASK="/*/{,tls/}${pthread}*" \
+		prepallstrip
+	# if user has stripping enabled and does not have split debug turned on,
+	# then leave the debugging sections in libpthread.
+	if ! has nostrip ${FEATURES} && ! has splitdebug ${FEATURES} ; then
+		${STRIP:-${CTARGET}-strip} --strip-debug "${ED}"$(alt_prefix)/*/libpthread-*.so
+	fi
+}
+
+src_install() {
+	if just_headers ; then
+		export ABI=default
+		glibc_headers_install
+		return
+	fi
+
+	foreach_abi glibc_do_src_install
+	src_strip
+}
+
+# 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
+
+	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 \
+		./ld-*.so --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
+
+	# 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
+
+	[[ ${ROOT} != "/" ]] && return 0
+	[[ -d ${ED}/$(get_libdir) ]] || return 0
+	[[ -z ${BOOTSTRAP_RAP} ]] && glibc_sanity_check
+}
+
+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 && [[ ${ROOT} == "/" ]] ; then
+		# Reload init ... if in a chroot or a diff init package, ignore
+		# errors from this step #253697
+		/sbin/telinit U 2>/dev/null
+
+		use compile-locales || run_locale_gen "${EROOT}"
+	fi
+
+	# Check for sanity of /etc/nsswitch.conf, take 2
+	if [[ -e ${EROOT}/etc/nsswitch.conf ]] && ! has_version sys-auth/libnss-nis ; then
+		local entry
+		for entry in passwd group shadow; do
+			if egrep -q "^[ \t]*${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
+}
diff --git a/sys-libs/glibc/metadata.xml b/sys-libs/glibc/metadata.xml
new file mode 100644
index 0000000..002e981
--- /dev/null
+++ b/sys-libs/glibc/metadata.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
+<pkgmetadata>
+<maintainer type="project">
+ <email>toolchain@gentoo.org</email>
+ <name>Gentoo Toolchain Project</name>
+</maintainer>
+<use>
+ <flag name="cet">Enable Intel Control-flow Enforcement Technology (needs binutils 2.29 and gcc 8)</flag>
+ <flag name="compile-locales">build *all* locales in src_install; this is generally meant for stage building only as it ignores /etc/locale.gen file and can be pretty slow</flag>
+ <flag name="gd">build memusage and memusagestat tools</flag>
+ <flag name="multiarch">enable optimizations for multiple CPU architectures (detected at runtime)</flag>
+ <flag name="nscd">Build, and enable support for, the Name Service Cache Daemon</flag>
+ <flag name="ssp">protect stack of glibc internals</flag>
+ <flag name="suid">Make internal pt_chown helper setuid -- not needed if using Linux and have /dev/pts mounted with gid=5</flag>
+ <flag name="systemtap">enable systemtap static probe points</flag>
+</use>
+<upstream>
+ <remote-id type="cpe">cpe:/a:gnu:glibc</remote-id>
+</upstream>
+</pkgmetadata>