AIX port, bug#490266.

This is from 2 upstream commits:

http://git.savannah.gnu.org/cgit/gawk.git/commit/?h=gawk-4.1-stable&id=21c8b6d547b12942775d675ead2994992285c04c
http://git.savannah.gnu.org/cgit/gawk.git/commit/?h=gawk-4.1-stable&id=29e3ae329c550b884169b7db20775cd74b95b77a

#diff --git a/extension/ChangeLog b/extension/ChangeLog
#index e01d6d1..4d1af22 100644
#--- a/extension/ChangeLog
#+++ b/extension/ChangeLog
#@@ -1,3 +1,20 @@
#+2013-10-23  Michael Haubenwallner <michael.haubenwallner@salomon.at>
#+
#+	Fix portability for AIX.
#+
#+	* inplace.c (_XOPEN_SOURCE): Define when not defined yet.
#+	(_XOPEN_SOURCE_EXTENDED): Ditto. Needs to define a number.
#+
#+2013-06-10         Arnold D. Robbins     <arnold@skeeve.com>
#+
#+	* configure.ac (AC_HEADER_MAJOR): New macro added.
#+	Add check for limits.h header.
#+	* filefuncs.c: Add the right stuff to get the major/minor macros.
#+	* readdir.c: Add include of limits.h appropriately wrapped.
#+
#+	Thanks to ICHII Takashi <ichii386@schweetheart.jp> for the reports
#+	and pointers.
#+
# 2013-05-09         Arnold D. Robbins     <arnold@skeeve.com>
# 
# 	* 4.1.0: Release tar ball made.
#diff --git a/extension/configure.ac b/extension/configure.ac
#index 53ed588..3ad03ed 100644
#--- a/extension/configure.ac
#+++ b/extension/configure.ac
#@@ -64,7 +64,8 @@ else
# 	AC_MSG_RESULT([no])
# fi
# 
#-AC_CHECK_HEADERS(dirent.h fnmatch.h time.h sys/time.h sys/select.h)
#+AC_HEADER_MAJOR
#+AC_CHECK_HEADERS(dirent.h fnmatch.h limits.h time.h sys/time.h sys/select.h)
# 
# AC_CHECK_FUNCS(fdopendir fnmatch gettimeofday \
# 		getdtablesize nanosleep select GetSystemTimeAsFileTime)
diff --git a/extension/configh.in b/extension/configh.in
index 9162ce4..02954ee 100644
--- a/extension/configh.in
+++ b/extension/configh.in
@@ -66,6 +66,9 @@
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
+/* Define to 1 if you have the <limits.h> header file. */
+#undef HAVE_LIMITS_H
+
 /* Define to 1 if you have the <memory.h> header file. */
 #undef HAVE_MEMORY_H
 
@@ -109,6 +112,14 @@
    */
 #undef LT_OBJDIR
 
+/* Define to 1 if `major', `minor', and `makedev' are declared in <mkdev.h>.
+   */
+#undef MAJOR_IN_MKDEV
+
+/* Define to 1 if `major', `minor', and `makedev' are declared in
+   <sysmacros.h>. */
+#undef MAJOR_IN_SYSMACROS
+
 /* Name of package */
 #undef PACKAGE
 
diff --git a/extension/configure b/extension/configure
index f848b9b..c3f8f1c 100755
--- a/extension/configure
+++ b/extension/configure
@@ -13885,7 +13885,57 @@ else
 $as_echo "no" >&6; }
 fi
 
-for ac_header in dirent.h fnmatch.h time.h sys/time.h sys/select.h
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether sys/types.h defines makedev" >&5
+$as_echo_n "checking whether sys/types.h defines makedev... " >&6; }
+if ${ac_cv_header_sys_types_h_makedev+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <sys/types.h>
+int
+main ()
+{
+return makedev(0, 0);
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_header_sys_types_h_makedev=yes
+else
+  ac_cv_header_sys_types_h_makedev=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_header_sys_types_h_makedev" >&5
+$as_echo "$ac_cv_header_sys_types_h_makedev" >&6; }
+
+if test $ac_cv_header_sys_types_h_makedev = no; then
+ac_fn_c_check_header_mongrel "$LINENO" "sys/mkdev.h" "ac_cv_header_sys_mkdev_h" "$ac_includes_default"
+if test "x$ac_cv_header_sys_mkdev_h" = xyes; then :
+
+$as_echo "#define MAJOR_IN_MKDEV 1" >>confdefs.h
+
+fi
+
+
+
+  if test $ac_cv_header_sys_mkdev_h = no; then
+    ac_fn_c_check_header_mongrel "$LINENO" "sys/sysmacros.h" "ac_cv_header_sys_sysmacros_h" "$ac_includes_default"
+if test "x$ac_cv_header_sys_sysmacros_h" = xyes; then :
+
+$as_echo "#define MAJOR_IN_SYSMACROS 1" >>confdefs.h
+
+fi
+
+
+  fi
+fi
+
+for ac_header in dirent.h fnmatch.h limits.h time.h sys/time.h sys/select.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
diff --git a/extension/filefuncs.c b/extension/filefuncs.c
index 1e8fc8d..9e637aa 100644
--- a/extension/filefuncs.c
+++ b/extension/filefuncs.c
@@ -46,6 +46,12 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#ifdef MAJOR_IN_MKDEV
+#include <sys/mkdev.h>
+#elif defined(MAJOR_IN_SYSMACROS)
+#include <sys/sysmacros.h>
+#endif
+
 #include "gawkapi.h"
 
 #include "gettext.h"
diff --git a/extension/inplace.c b/extension/inplace.c
index ded4746..69d452a 100644
--- a/extension/inplace.c
+++ b/extension/inplace.c
@@ -27,8 +27,12 @@
 #include <config.h>
 #endif
 
-#define _XOPEN_SOURCE
-#define _XOPEN_SOURCE_EXTENDED
+#ifndef _XOPEN_SOURCE
+# define _XOPEN_SOURCE
+#endif
+#ifndef _XOPEN_SOURCE_EXTENDED
+# define _XOPEN_SOURCE_EXTENDED 1
+#endif
 
 #include <stdio.h>
 #include <assert.h>
diff --git a/extension/readdir.c b/extension/readdir.c
index 5ca4dc6..c2a626a 100644
--- a/extension/readdir.c
+++ b/extension/readdir.c
@@ -44,6 +44,10 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 
+#ifdef HAVE_LIMITS_H
+#include <limits.h>
+#endif
+
 #ifdef HAVE_DIRENT_H
 #include <dirent.h>
 #else