Support compilers defaulting to PIE

[thirdparty/glibc.git] / configure.ac

dnl Process this file with autoconf to produce a configure script.
dnl Note we do not use AC_PREREQ here!  See aclocal.m4 for what we use instead.
AC_INIT([GNU C Library], [(see version.h)], [http://sourceware.org/bugzilla/], [glibc])
AC_CONFIG_SRCDIR([include/features.h])
AC_CONFIG_HEADERS([config.h])
AC_CONFIG_AUX_DIR([scripts])

ACX_PKGVERSION([GNU libc])
ACX_BUGURL([http://www.gnu.org/software/libc/bugs.html])
AC_DEFINE_UNQUOTED([PKGVERSION], ["$PKGVERSION"],
		   [Package description])
AC_DEFINE_UNQUOTED([REPORT_BUGS_TO], ["$REPORT_BUGS_TO"],
		   [Bug reporting address])

# Glibc should not depend on any header files
AC_DEFUN([_AC_INCLUDES_DEFAULT_REQUIREMENTS],
  [m4_divert_text([DEFAULTS],
    [ac_includes_default='/* none */'])])

# We require GCC, and by default use its preprocessor.  Override AC_PROG_CPP
# here to work around the Autoconf issue discussed in
# <http://sourceware.org/ml/libc-alpha/2013-01/msg00721.html>.
AC_DEFUN([AC_PROG_CPP],
[AC_REQUIRE([AC_PROG_CC])dnl
AC_ARG_VAR([CPP],      [C preprocessor])dnl
_AC_ARG_VAR_CPPFLAGS()dnl
# On Suns, sometimes $CPP names a directory.
if test -n "$CPP" && test -d "$CPP"; then
  CPP=
fi
if test -z "$CPP"; then
  CPP="$CC -E"
fi
AC_SUBST(CPP)dnl
])# AC_PROG_CPP

# We require GCC.  Override _AC_PROG_CC_C89 here to work around the Autoconf
# issue discussed in
# <http://sourceware.org/ml/libc-alpha/2013-01/msg00757.html>.
AC_DEFUN([_AC_PROG_CC_C89], [[$1]])

dnl This is here so we can set $subdirs directly based on configure fragments.
AC_CONFIG_SUBDIRS()

AC_CANONICAL_HOST

AC_PROG_CC
if test $host != $build; then
  AC_CHECK_PROGS(BUILD_CC, gcc cc)
fi
AC_SUBST(cross_compiling)
AC_PROG_CPP
AC_CHECK_TOOL(READELF, readelf, false)

# We need the C++ compiler only for testing.
AC_PROG_CXX
# It's useless to us if it can't link programs (e.g. missing -lstdc++).
AC_CACHE_CHECK([whether $CXX can link programs], libc_cv_cxx_link_ok, [dnl
AC_LANG_PUSH([C++])
AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
	       [libc_cv_cxx_link_ok=yes],
	       [libc_cv_cxx_link_ok=no])
AC_LANG_POP([C++])])
AS_IF([test $libc_cv_cxx_link_ok != yes], [CXX=])

if test "`cd $srcdir; /bin/pwd`" = "`/bin/pwd`"; then
  AC_MSG_ERROR([you must configure in a separate build directory])
fi

# This will get text that should go into config.make.
config_vars=

# Check for a --with-gd argument and set libgd-LDFLAGS in config.make.
AC_ARG_WITH([gd],
	    AC_HELP_STRING([--with-gd=DIR],
			   [find libgd include dir and library with prefix DIR]),
	    [dnl
case "$with_gd" in
yes|''|no) ;;
*) libgd_include="-I$withval/include"
   libgd_ldflags="-L$withval/lib" ;;
esac
])
AC_ARG_WITH([gd-include],
	    AC_HELP_STRING([--with-gd-include=DIR],
			   [find libgd include files in DIR]),
	    [dnl
case "$with_gd_include" in
''|no) ;;
*) libgd_include="-I$withval" ;;
esac
])
AC_ARG_WITH([gd-lib],
	    AC_HELP_STRING([--with-gd-lib=DIR],
			   [find libgd library files in DIR]),
	    [dnl
case "$with_gd_lib" in
''|no) ;;
*) libgd_ldflags="-L$withval" ;;
esac
])

if test -n "$libgd_include"; then
  config_vars="$config_vars
CFLAGS-memusagestat.c = $libgd_include"
fi
if test -n "$libgd_ldflags"; then
  config_vars="$config_vars
libgd-LDFLAGS = $libgd_ldflags"
fi

dnl Arguments to specify presence of other packages/features.
AC_ARG_WITH([fp],
	    AC_HELP_STRING([--with-fp],
			   [if using floating-point hardware @<:@default=yes@:>@]),
	    [with_fp=$withval],
	    [with_fp=yes])
AC_SUBST(with_fp)
AC_ARG_WITH([binutils],
	    AC_HELP_STRING([--with-binutils=PATH],
			   [specify location of binutils (as and ld)]),
	    [path_binutils=$withval],
	    [path_binutils=''])
AC_ARG_WITH([selinux],
	    AC_HELP_STRING([--with-selinux],
			   [if building with SELinux support]),
	    [with_selinux=$withval],
	    [with_selinux=auto])

AC_ARG_WITH([headers],
	    AC_HELP_STRING([--with-headers=PATH],
			   [location of system headers to use
			    (for example /usr/src/linux/include)
			    @<:@default=compiler default@:>@]),
	    [sysheaders=$withval],
	    [sysheaders=''])
AC_SUBST(sysheaders)

AC_SUBST(use_default_link)
AC_ARG_WITH([default-link],
	    AC_HELP_STRING([--with-default-link],
			   [do not use explicit linker scripts]),
	    [use_default_link=$withval],
	    [use_default_link=default])

AC_ARG_ENABLE([sanity-checks],
	      AC_HELP_STRING([--disable-sanity-checks],
			     [really do not use threads (should not be used except in special situations) @<:@default=yes@:>@]),
	      [enable_sanity=$enableval],
	      [enable_sanity=yes])

AC_ARG_ENABLE([shared],
	      AC_HELP_STRING([--enable-shared],
			     [build shared library @<:@default=yes if GNU ld@:>@]),
	      [shared=$enableval],
	      [shared=yes])
AC_ARG_ENABLE([profile],
	      AC_HELP_STRING([--enable-profile],
			     [build profiled library @<:@default=no@:>@]),
	      [profile=$enableval],
	      [profile=no])

AC_ARG_ENABLE([hardcoded-path-in-tests],
	      AC_HELP_STRING([--enable-hardcoded-path-in-tests],
			     [hardcode newly built glibc path in tests @<:@default=no@:>@]),
	      [hardcoded_path_in_tests=$enableval],
	      [hardcoded_path_in_tests=no])
AC_SUBST(hardcoded_path_in_tests)

AC_ARG_ENABLE([stackguard-randomization],
	      AC_HELP_STRING([--enable-stackguard-randomization],
			     [initialize __stack_chk_guard canary with a random number at program start]),
	      [enable_stackguard_randomize=$enableval],
	      [enable_stackguard_randomize=no])
if test "$enable_stackguard_randomize" = yes; then
  AC_DEFINE(ENABLE_STACKGUARD_RANDOMIZE)
fi

AC_ARG_ENABLE([lock-elision],
	      AC_HELP_STRING([--enable-lock-elision[=yes/no]],
			     [Enable lock elision for pthread mutexes by default]),
	      [enable_lock_elision=$enableval],
	      [enable_lock_elision=no])
AC_SUBST(enable_lock_elision)
if test "$enable_lock_elision" = yes ; then
  AC_DEFINE(ENABLE_LOCK_ELISION)
fi

dnl Generic infrastructure for drop-in additions to libc.
AC_ARG_ENABLE([add-ons],
	      AC_HELP_STRING([--enable-add-ons@<:@=DIRS...@:>@],
			     [configure and build add-ons in DIR1,DIR2,...
			      search for add-ons if no parameter given]),
			     , [enable_add_ons=yes])

AC_ARG_ENABLE([hidden-plt],
	      AC_HELP_STRING([--disable-hidden-plt],
			     [do not hide internal function calls to avoid PLT]),
	      [hidden=$enableval],
	      [hidden=yes])
if test "x$hidden" = xno; then
  AC_DEFINE(NO_HIDDEN)
fi

AC_ARG_ENABLE([bind-now],
	      AC_HELP_STRING([--enable-bind-now],
			     [disable lazy relocations in DSOs]),
	      [bindnow=$enableval],
	      [bindnow=no])
AC_SUBST(bindnow)

dnl On some platforms we cannot use dynamic loading.  We must provide
dnl static NSS modules.
AC_ARG_ENABLE([static-nss],
	      AC_HELP_STRING([--enable-static-nss],
			     [build static NSS modules @<:@default=no@:>@]),
	      [static_nss=$enableval],
	      [static_nss=no])
dnl Enable static NSS also if we build no shared objects.
if test x"$static_nss" = xyes || test x"$shared" = xno; then
  static_nss=yes
  AC_DEFINE(DO_STATIC_NSS)
fi

AC_ARG_ENABLE([force-install],
	      AC_HELP_STRING([--disable-force-install],
			     [don't force installation of files from this package, even if they are older than the installed files]),
	      [force_install=$enableval],
	      [force_install=yes])
AC_SUBST(force_install)

AC_ARG_ENABLE([maintainer-mode],
	      AC_HELP_STRING([--enable-maintainer-mode],
			     [enable make rules and dependencies not useful (and sometimes confusing) to the casual installer]),
	      [maintainer=$enableval],
	      [maintainer=no])

dnl On some platforms we allow dropping compatibility with all kernel
dnl versions.
AC_ARG_ENABLE([kernel],
	      AC_HELP_STRING([--enable-kernel=VERSION],
			     [compile for compatibility with kernel not older than VERSION]),
	      [minimum_kernel=$enableval],
	      [])
dnl Prevent unreasonable values.
if test "$minimum_kernel" = yes || test "$minimum_kernel" = no; then
  # Better nothing than this.
  minimum_kernel=""
else
  if test "$minimum_kernel" = current; then
    minimum_kernel=`uname -r 2>/dev/null` || minimum_kernel=
  fi
fi

dnl For the development we sometimes want gcc to issue even more warnings.
dnl This is not the default since many of the extra warnings are not
dnl appropriate.
AC_ARG_ENABLE([all-warnings],
	      AC_HELP_STRING([--enable-all-warnings],
			     [enable all useful warnings gcc can issue]),
	      [all_warnings=$enableval],
	      [])
AC_SUBST(all_warnings)

AC_ARG_ENABLE([werror],
	      AC_HELP_STRING([--disable-werror],
			     [do not build with -Werror]),
	      [enable_werror=$enableval],
	      [enable_werror=yes])
AC_SUBST(enable_werror)

AC_ARG_ENABLE([multi-arch],
	      AC_HELP_STRING([--enable-multi-arch],
			     [enable single DSO with optimizations for multiple architectures]),
	      [multi_arch=$enableval],
	      [multi_arch=default])

AC_ARG_ENABLE([nss-crypt],
	      AC_HELP_STRING([--enable-nss-crypt],
			     [enable libcrypt to use nss]),
	      [nss_crypt=$enableval],
	      [nss_crypt=no])
if test x$nss_crypt = xyes; then
  nss_includes=-I$(nss-config --includedir 2>/dev/null)
  if test $? -ne 0; then
    AC_MSG_ERROR([cannot find include directory with nss-config])
  fi
  old_CFLAGS="$CFLAGS"
  CFLAGS="$CFLAGS $nss_includes"
  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([typedef int PRBool;
#include <hasht.h>
#include <nsslowhash.h>
void f (void) { NSSLOW_Init (); }])],
	     libc_cv_nss_crypt=yes,
	     AC_MSG_ERROR([
cannot find NSS headers with lowlevel hash function interfaces]))
  old_LIBS="$LIBS"
  LIBS="$LIBS -lfreebl3"
  AC_LINK_IFELSE([AC_LANG_PROGRAM([typedef int PRBool;
#include <hasht.h>
#include <nsslowhash.h>],
				  [NSSLOW_Init();])],
		 libc_cv_nss_crypt=yes,
		 AC_MSG_ERROR([
cannot link program using lowlevel NSS hash functions]))
  CFLAGS="$old_CFLAGS"
  LIBS="$old_LIBS"
else
  libc_cv_nss_crypt=no
fi
AC_SUBST(libc_cv_nss_crypt)


AC_ARG_ENABLE([obsolete-rpc],
              AC_HELP_STRING([--enable-obsolete-rpc],
                             [build and install the obsolete RPC code for link-time usage]),
              [link_obsolete_rpc=$enableval],
              [link_obsolete_rpc=no])
AC_SUBST(link_obsolete_rpc)

if test "$link_obsolete_rpc" = yes; then
  AC_DEFINE(LINK_OBSOLETE_RPC)
fi

AC_ARG_ENABLE([systemtap],
              [AS_HELP_STRING([--enable-systemtap],
	       [enable systemtap static probe points @<:@default=no@:>@])],
              [systemtap=$enableval],
	      [systemtap=no])
if test "x$systemtap" != xno; then
  AC_CACHE_CHECK([for systemtap static probe support], libc_cv_sdt, [dnl
  old_CFLAGS="$CFLAGS"
  CFLAGS="-std=gnu99 $CFLAGS"
  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[#include <sys/sdt.h>
void foo (int i, void *p)
{
  asm ("" STAP_PROBE_ASM (foo, bar, STAP_PROBE_ASM_TEMPLATE (2)) ""
       :: STAP_PROBE_ASM_OPERANDS (2, i, p));
}]])], [libc_cv_sdt=yes], [libc_cv_sdt=no])
  CFLAGS="$old_CFLAGS"])
  if test $libc_cv_sdt = yes; then
    AC_DEFINE([USE_STAP_PROBE])
  elif test "x$systemtap" != xauto; then
    AC_MSG_FAILURE([systemtap support needs sys/sdt.h with asm support])
  fi
fi

AC_ARG_ENABLE([build-nscd],
	      [AS_HELP_STRING([--disable-build-nscd],
	       [disable building and installing the nscd daemon])],
	      [build_nscd=$enableval],
	      [build_nscd=default])
AC_SUBST(build_nscd)

# Note the use of $use_nscd is near the bottom of the file.
AC_ARG_ENABLE([nscd],
	      [AS_HELP_STRING([--disable-nscd],
	       [library functions will not contact the nscd daemon])],
	      [use_nscd=$enableval],
	      [use_nscd=yes])

AC_ARG_ENABLE([pt_chown],
	      [AS_HELP_STRING([--enable-pt_chown],
	       [Enable building and installing pt_chown])],
	      [build_pt_chown=$enableval],
	      [build_pt_chown=no])
AC_SUBST(build_pt_chown)
if test "$build_pt_chown" = yes; then
  AC_DEFINE(HAVE_PT_CHOWN)
fi

# The abi-tags file uses a fairly simplistic model for name recognition that
# can't distinguish i486-pc-linux-gnu fully from i486-pc-gnu.  So we mutate a
# $host_os of `gnu*' here to be `gnu-gnu*' just so that it can tell.
# This doesn't get used much beyond that, so it's fairly safe.
case "$host_os" in
linux*)
  ;;
gnu*)
  host_os=`echo $host_os | sed -e 's/gnu/gnu-gnu/'`
  ;;
esac

AC_ARG_ENABLE([mathvec],
	      [AS_HELP_STRING([--enable-mathvec],
	      [Enable building and installing mathvec @<:@default depends on architecture@:>@])],
	      [build_mathvec=$enableval],
	      [build_mathvec=notset])

# We keep the original values in `$config_*' and never modify them, so we
# can write them unchanged into config.make.  Everything else uses
# $machine, $vendor, and $os, and changes them whenever convenient.
config_machine=$host_cpu config_vendor=$host_vendor config_os=$host_os

# Don't allow vendor == "unknown"
test "$config_vendor" = unknown && config_vendor=
config_os="`echo $config_os | sed 's/^unknown-//'`"

# Some configurations imply other options.
elf=yes

# The configure fragment of an add-on port can modify these to supplement
# or override the table in the case statement below.  No fragment should
# ever change the config_* variables, however.
machine=$config_machine
vendor=$config_vendor
os=$config_os
base_os=''

submachine=
AC_ARG_WITH([cpu],
	    AS_HELP_STRING([--with-cpu=CPU], [select code for CPU variant]),
	    [dnl
  case "$withval" in
  yes|'') AC_MSG_ERROR([--with-cpu requires an argument]) ;;
  no) ;;
  *) submachine="$withval" ;;
  esac
])

# An preconfigure script can set this when it wants to disable the sanity
# check below.
libc_config_ok=no

dnl Let sysdeps/*/preconfigure act here, like they can in add-ons.
LIBC_PRECONFIGURE([$srcdir], [for sysdeps])

dnl Having this here, though empty, makes sure that if add-ons' fragments
dnl do AC_CONFIG_SUBDIRS([some-dir]), which just sets $subdirs, then
dnl our AC_OUTPUT will actually use it.
AC_CONFIG_SUBDIRS()

case "$enable_add_ons" in
''|no) add_ons= ;;
yes|'*')
 add_ons=`cd $srcdir && ls -d 2> /dev/null */configure */sysdeps |
	  sed 's@/[[^/]]*$@@' | sort | uniq`
	 add_ons_automatic=yes
	 ;;
*) add_ons=`echo "$enable_add_ons" | sed 's/,/ /g'`
       add_ons_automatic=no ;;
esac

configured_add_ons=
add_ons_sfx=
add_ons_pfx=
if test x"$add_ons" != x; then
  for f in $add_ons; do
    # Some sanity checks
    case "$f" in
    crypt)
      AC_MSG_ERROR([
*** It seems that you're using an old \`crypt' add-on.  crypt is now
*** part of glibc and using the old add-on will not work with this
*** release.  Start again with fresh sources and without the old
*** \`crypt' add-on.])
    ;;
    localedata)
      AC_MSG_ERROR([
*** It seems that you're using an old \`localedata' add-on.  localedata
*** is now part of glibc and using the old add-on will not work with
*** this release.  Start again with fresh sources and without the old
*** \`localedata' add-on.])
    ;;
    esac
  done

  # Now source each add-on's configure fragment.
  # The fragments can use $srcdir/$libc_add_on to find themselves,
  # and test $add_ons_automatic to see if they were explicitly requested.
  # A fragment can clear (or even change) $libc_add_on to affect
  # whether it goes into the list to be actually used in the build.
  use_add_ons=
  for libc_add_on in $add_ons; do
    # Test whether such a directory really exists.
    # It can be absolute, or relative to $srcdir, or relative to the build dir.
    case "$libc_add_on" in
    /*)
      libc_add_on_srcdir=$libc_add_on
      ;;
    *)
      test -d "$srcdir/$libc_add_on" || {
	if test -d "$libc_add_on"; then
	  libc_add_on="`pwd`/$libc_add_on"
	else
	  AC_MSG_ERROR(add-on directory \"$libc_add_on\" does not exist)
	fi
      }
      libc_add_on_srcdir=$srcdir/$libc_add_on
      ;;
    esac

    libc_add_on_frag=$libc_add_on_srcdir/configure
    libc_add_on_canonical=
    libc_add_on_config_subdirs=
    if test -r "$libc_add_on_frag"; then
      AC_MSG_NOTICE(running configure fragment for add-on $libc_add_on)
      libc_add_on_canonical=unknown
      libc_add_on_subdirs=
      . "$libc_add_on_frag"
      test -z "$libc_add_on" || {
	configured_add_ons="$configured_add_ons $libc_add_on"
	if test "x$libc_add_on_canonical" = xunknown; then
	  AC_MSG_ERROR(fragment must set \$libc_add_on_canonical)
	fi
	for d in $libc_add_on_subdirs; do
	  case "$libc_add_on" in
	  /*) subdir_srcdir="$libc_add_on" ;;
	  *) subdir_srcdir="\$(..)$libc_add_on" ;;
	  esac
	  case "$d" in
	  .)
	    d="${libc_add_on_canonical:-$libc_add_on}"
	    ;;
	  /*)
	    subdir_srcdir="$d"
	    ;;
	  *)
	    subdir_srcdir="$subdir_srcdir/$d"
	    ;;
	  esac
	  d=`echo "$d" | sed 's@/*$@@;s@^.*/@@'`
	  add_on_subdirs="$add_on_subdirs $d"
	  test "$subdir_srcdir" = "\$(..)$d" || config_vars="$config_vars
$d-srcdir = $subdir_srcdir"
	done
	for d in $libc_add_on_config_subdirs; do
	  case "$d" in
	  /*) AC_MSG_ERROR(dnl
fragment uses absolute path in \$libc_add_on_config_subdirs) ;;
	  esac
	  if test ! -d "$libc_add_on_srcdir/$d"; then
	    AC_MSG_ERROR(fragment wants to configure missing directory $d)
	  fi
	  case "$libc_add_on" in
	  /*) AC_MSG_ERROR(dnl
relative path required for add-on using \$libc_add_on_config_subdirs) ;;
	  esac
	  subdirs="$subdirs $libc_add_on/$d"
	done
      }
    fi
    if test -n "$libc_add_on"; then
      LIBC_PRECONFIGURE([$libc_add_on_srcdir], [add-on $libc_add_on for])
      use_add_ons="$use_add_ons $libc_add_on"
      add_ons_pfx="$add_ons_pfx $libc_add_on/"
      test -z "$libc_add_on_canonical" ||
      add_ons_sfx="$add_ons_sfx /$libc_add_on_canonical"
    fi
  done
  # Use echo to strip excess whitespace.
  add_ons="`echo $use_add_ons`"
fi
AC_SUBST(add_ons)
AC_SUBST(add_on_subdirs)


###
### I put this here to prevent those annoying emails from people who cannot
### read and try to compile glibc on unsupported platforms.  --drepper
###
### By using the undocumented --enable-hacker-mode option for configure
### one can skip this test to make the configuration not fail for unsupported
### platforms.
###
if test -z "$enable_hacker_mode" && test x"$libc_config_ok" != xyes; then
  case "$machine-$host_os" in
  *-linux* | *-gnu*)
    ;;
  *)
    echo "*** The GNU C library is currently not available for this platform."
    echo "*** So far nobody cared to port it and if there is no volunteer it"
    echo "*** might never happen.  So, if you have interest to see glibc on"
    echo "*** this platform visit"
    echo "***	http://www.gnu.org/software/libc/porting.html"
    echo "*** and join the group of porters"
    exit 1
    ;;
  esac
fi

# Set base_machine if not set by a preconfigure fragment.
test -n "$base_machine" || base_machine=$machine
AC_SUBST(base_machine)

# For the multi-arch option we need support in the assembler & linker.
AC_CACHE_CHECK([for assembler and linker STT_GNU_IFUNC support],
	       libc_cv_ld_gnu_indirect_function, [dnl
cat > conftest.S <<EOF
.type foo,%gnu_indirect_function
foo:
.globl _start
_start:
.globl __start
__start:
.data
#ifdef _LP64
.quad foo
#else
.long foo
#endif
EOF
libc_cv_ld_gnu_indirect_function=no
if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
	    -nostartfiles -nostdlib \
	    -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then
  # Do a link to see if the backend supports IFUNC relocs.
  $READELF -r conftest 1>&AS_MESSAGE_LOG_FD
  LC_ALL=C $READELF -r conftest | grep 'no relocations' >/dev/null || {
    libc_cv_ld_gnu_indirect_function=yes
  }
fi
rm -f conftest*])

AC_MSG_CHECKING(whether .text pseudo-op must be used)
AC_CACHE_VAL(libc_cv_dot_text, [dnl
cat > conftest.s <<EOF
.text
EOF
libc_cv_dot_text=
if AC_TRY_COMMAND(${CC-cc} $ASFLAGS -c conftest.s 1>&AS_MESSAGE_LOG_FD); then
  libc_cv_dot_text=.text
fi
rm -f conftest*])
if test -z "$libc_cv_dot_text"; then
  AC_MSG_RESULT(no)
else
  AC_MSG_RESULT(yes)
fi

if test x"$libc_cv_ld_gnu_indirect_function" != xyes; then
  if test x"$multi_arch" = xyes; then
    AC_MSG_ERROR([--enable-multi-arch support requires assembler and linker support])
  else
    multi_arch=no
  fi
fi
multi_arch_d=
if test x"$multi_arch" != xno; then
  multi_arch_d=/multiarch
fi

# Compute the list of sysdep directories for this configuration.
# This can take a while to compute.
sysdep_dir=$srcdir/sysdeps
AC_MSG_CHECKING(sysdep dirs)
dnl We need to use [ and ] for other purposes for a while now.
changequote(,)dnl
# Make sco3.2v4 become sco3.2.4 and sunos4.1.1_U1 become sunos4.1.1.U1.
os="`echo $os | sed 's/\([0-9A-Z]\)[v_]\([0-9A-Z]\)/\1.\2/g'`"

test "x$base_os" != x || case "$os" in
gnu*)
  base_os=mach/hurd ;;
linux*)
  base_os=unix/sysv ;;
esac

# For sunos4.1.1, try sunos4.1.1, then sunos4.1, then sunos4, then sunos.
tail=$os
ostry=$os
while o=`echo $tail | sed 's/\.[^.]*$//'`; test $o != $tail; do
  ostry="$ostry /$o"
  tail=$o
done
o=`echo $tail | sed 's/[0-9]*$//'`
if test $o != $tail; then
  ostry="$ostry /$o"
fi
# For linux-gnu, try linux-gnu, then linux.
o=`echo $tail | sed 's/-.*$//'`
if test $o != $tail; then
  ostry="$ostry /$o"
fi

# For unix/sysv/sysv4, try unix/sysv/sysv4, then unix/sysv, then unix.
base=
tail=$base_os
while b=`echo $tail | sed 's@^\(.*\)/\([^/]*\)$@& \1@'`; test -n "$b"; do
  set $b
  base="$base /$1"
  tail="$2"
done

# For sparc/sparc32, try sparc/sparc32 and then sparc.
mach=
tail=$machine${submachine:+/$submachine}
while m=`echo $tail | sed 's@^\(.*\)/\([^/]*\)$@& \1@'`; test -n "$m"; do
  set $m
  # Prepend the machine's FPU directory unless --without-fp.
  if test "$with_fp" = yes; then
    maybe_fpu=/fpu
  else
    maybe_fpu=/nofpu
  fi
  # For each machine term, try it with and then without /multiarch.
  for try_fpu in $maybe_fpu ''; do
    for try_multi in $multi_arch_d ''; do
      mach="$mach /$1$try_fpu$try_multi"
    done
  done
  tail="$2"
done

dnl We are done with glob and regexp uses of [ and ]; return to autoconf.
changequote([,])dnl

# Find what sysdep directories exist.
sysnames_add_ons=
sysnames=
for b in $base ''; do
  for m0 in $mach ''; do
    for v in /$vendor ''; do
      test "$v" = / && continue
      for o in /$ostry ''; do
	test "$o" = / && continue
	for m in $mach ''; do
	  for d in $add_ons_pfx ''; do
	    for a in $add_ons_sfx ''; do
	      try_suffix="$m0$b$v$o$m"
	      if test -n "$try_suffix"; then
		try_srcdir="${srcdir}/"
		case "$d" in
		/*) try_srcdir= ;;
		esac
		try="${d}sysdeps$try_suffix$a"
		test -n "$enable_debug_configure" &&
		echo "$0 [DEBUG]: try $try" >&2
		if test -d "$try_srcdir$try"; then
		  sysnames="$sysnames $try"
		  { test -n "$o" || test -n "$b"; } && os_used=t
		  { test -n "$m" || test -n "$m0"; } && machine_used=t
		  case x${m0:-$m} in
		  x*/$submachine) submachine_used=t ;;
		  esac
		  if test -n "$d"; then
		    case "$sysnames_add_ons" in
		    *" $d "*) ;;
		    *|'') sysnames_add_ons="$sysnames_add_ons $d" ;;
		    esac
		  fi
		fi
	      fi
	    done
	  done
	done
      done
    done
  done
done

# If the assembler supports gnu_indirect_function symbol type and the
# architecture supports multi-arch, we enable multi-arch by default.
case $sysnames_add_ons$sysnames in
*"$multi_arch_d"*)
  ;;
*)
  test x"$multi_arch" = xdefault && multi_arch=no
  ;;
esac
if test x"$multi_arch" != xno; then
  AC_DEFINE(USE_MULTIARCH)
fi
AC_SUBST(multi_arch)

if test -z "$os_used" && test "$os" != none; then
  AC_MSG_ERROR(Operating system $os is not supported.)
fi
if test -z "$machine_used" && test "$machine" != none; then
  AC_MSG_ERROR(The $machine is not supported.)
fi
if test -z "$submachine_used" && test -n "$submachine"; then
  AC_MSG_ERROR(The $submachine subspecies of $host_cpu is not supported.)
fi
AC_SUBST(submachine)

# We have now validated the configuration.

# Expand the list of system names into a full list of directories
# from each element's parent name and Implies file (if present).
set $sysnames
names=
while test $# -gt 0; do
  name=$1
  shift

  case " $names " in *" $name "*)
    # Already in the list.
    continue
  esac

  # Report each name as we discover it, so there is no long pause in output.
  echo $ECHO_N "$name $ECHO_C" >&AS_MESSAGE_FD

  name_base=`echo $name | sed -e 's@\(.*sysdeps\)/.*@\1@'`

  case $name in
    /*) xsrcdir= ;;
    *)  xsrcdir=$srcdir/ ;;
  esac
  test -n "$enable_debug_configure" &&
  echo "[DEBUG]: name/Implies $xsrcdir$name/Implies" >&2

  for implies_file in Implies Implies-before Implies-after; do
    implies_type=`echo $implies_file | sed s/-/_/`
    eval ${implies_type}=
    if test -f $xsrcdir$name/$implies_file; then
      # Collect more names from the `Implies' file (removing comments).
      implied_candidate="`sed 's/#.*$//' < $xsrcdir$name/$implies_file`"
      for x in $implied_candidate; do
	found=no
	if test -d $xsrcdir$name_base/$x; then
	  eval "${implies_type}=\"\$${implies_type} \$name_base/\$x\""
	  found=yes
	fi
	for d in $add_ons_pfx ''; do
	  try="${d}sysdeps/$x"
	  case $d in
	   /*) try_srcdir= ;;
	   *) try_srcdir=$srcdir/ ;;
	  esac
	  test -n "$enable_debug_configure" &&
	   echo "[DEBUG]: $name $implies_file $x try($d) {$try_srcdir}$try" >&2
	  if test $try != $xsrcdir$name_base/$x && test -d $try_srcdir$try;
	  then
	    eval "${implies_type}=\"\$${implies_type} \$try\""
	    found=yes
	    case "$sysnames_add_ons" in
	    *" $d "*) ;;
	    *|'') sysnames_add_ons="$sysnames_add_ons $d" ;;
	    esac
	  fi
	done
	if test $found = no; then
	  AC_MSG_WARN($name/$implies_file specifies nonexistent $x)
	fi
      done
    fi
  done

  # Add NAME to the list of names.
  names="$names $name"

  # Find the parent of NAME, using the empty string if it has none.
changequote(,)dnl
  parent="`echo $name | sed -n -e 's=/[^/]*$==' -e '/sysdeps$/q' -e p`"
changequote([,])dnl

  test -n "$enable_debug_configure" &&
    echo "[DEBUG]: $name Implies='$Implies' rest='$*' parent='$parent' \
Implies_before='$Implies_before' Implies_after='$Implies_after'" >&2

  # Add the names implied by NAME, and NAME's parent (if it has one), to
  # the list of names to be processed (the argument list).  We prepend the
  # implied names to the list and append the parent.  We want implied
  # directories to come before further directories inferred from the
  # configuration components; this ensures that for sysv4, unix/common
  # (implied by unix/sysv/sysv4) comes before unix/sysv (in ostry (here $*)
  # after sysv4).
  sysnames="`echo $Implies $* $Implies_before $parent $Implies_after`"
  test -n "$sysnames" && set $sysnames
done

# Add the default directories.
default_sysnames="sysdeps/generic"
sysnames="$names $default_sysnames"
AC_SUBST(sysnames)
# The other names were emitted during the scan.
AC_MSG_RESULT($default_sysnames)

# Collect the list of add-ons that supply partial sysdeps trees.
sysdeps_add_ons=
for add_on in $add_ons; do
  case "$add_on" in
  /*) xsrcdir= ;;
  *) xsrcdir="$srcdir/" ;;
  esac

  test -d "$xsrcdir$add_on/sysdeps" || {
    case "$configured_add_ons " in
    *" $add_on "*) ;;
    *|'')
      AC_MSG_ERROR(add-on $add_on has no configure fragment or sysdeps tree)
      ;;
    esac
    continue
  }

  sysdeps_add_ons="$sysdeps_add_ons $add_on"
  case "$sysnames_add_ons" in
  *" $add_on/ "*) ;;
  *|'')
    AC_MSG_WARN(add-on $add_on contributed no sysdeps directories)
    continue ;;
  esac

  found=no
  for d in $sysnames; do
    case "$d" in
    $add_on/sysdeps/*) ;;
    *) continue ;;
    esac
    (cd "$xsrcdir$d" && for f in *[[!~]]; do
       case "$f" in
       sys|bits)
	 for ff in $f/*.h; do
	   test -d "$ff" || { test -e "$ff" && exit 88; }
	 done
	 ;;
       *)
	 test -d "$f" || { test -e "$f" && exit 88; }
	 ;;
       esac
     done)
    if test $? -eq 88; then
      found=yes
      break
    fi
  done
  if test $found = no; then
    AC_MSG_WARN(add-on $add_on contributed no useful sysdeps directories)
  fi
done
AC_SUBST(sysdeps_add_ons)


### Locate tools.

AC_PROG_INSTALL
if test "$INSTALL" = "${srcdir}/scripts/install-sh -c"; then
  # The makefiles need to use a different form to find it in $srcdir.
  INSTALL='\$(..)./scripts/install-sh -c'
fi
AC_PROG_LN_S

LIBC_PROG_BINUTILS

# Accept binutils 2.22 or newer.
AC_CHECK_PROG_VER(AS, $AS, --version,
		  [GNU assembler.* \([0-9]*\.[0-9.]*\)],
		  [2.1[0-9][0-9]*|2.2[2-9]*|2.[3-9][0-9]*|[3-9].*|[1-9][0-9]*],
		  AS=: critic_missing="$critic_missing as")
AC_CHECK_PROG_VER(LD, $LD, --version,
		  [GNU ld.* \([0-9][0-9]*\.[0-9.]*\)],
		  [2.1[0-9][0-9]*|2.2[2-9]*|2.[3-9][0-9]*|[3-9].*|[1-9][0-9]*],
		  LD=: critic_missing="$critic_missing ld")

# These programs are version sensitive.
AC_CHECK_TOOL_PREFIX
AC_CHECK_PROG_VER(MAKE, gnumake gmake make, --version,
  [GNU Make[^0-9]*\([0-9][0-9.]*\)],
  [3.79* | 3.[89]* | [4-9].* | [1-9][0-9]*], critic_missing="$critic_missing make")

AC_CHECK_PROG_VER(MSGFMT, gnumsgfmt gmsgfmt msgfmt, --version,
  [GNU gettext.* \([0-9]*\.[0-9.]*\)],
  [0.10.3[6-9]* | 0.10.[4-9][0-9]* | 0.1[1-9]* | 0.[2-9][0-9]* | [1-9].*],
  MSGFMT=: aux_missing="$aux_missing msgfmt")
AC_CHECK_PROG_VER(MAKEINFO, makeinfo, --version,
  [GNU texinfo.* \([0-9][0-9.]*\)],
  [4.[7-9]*|4.[1-9][0-9]*|[5-9].*],
  MAKEINFO=: aux_missing="$aux_missing makeinfo")
AC_CHECK_PROG_VER(SED, sed, --version,
  [GNU sed[^0-9]* \([0-9]*\.[0-9.]*\)],
  [3.0[2-9]*|3.[1-9]*|[4-9]*],
  SED=: aux_missing="$aux_missing sed")
AC_CHECK_PROG_VER(AWK, gawk, --version,
  [GNU Awk[^0-9]*\([0-9][0-9.]*\)],
  [3.1.[2-9]*|3.[2-9]*|[4-9]*], critic_missing="$critic_missing gawk")

AC_CACHE_CHECK([if $CC is sufficient to build libc], libc_cv_compiler_ok, [
AC_TRY_COMPILE([], [
#if !defined __GNUC__ || __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
#error insufficient compiler
#endif],
	       [libc_cv_compiler_ok=yes],
	       [libc_cv_compiler_ok=no])])
AS_IF([test $libc_cv_compiler_ok != yes],
      [critic_missing="$critic_missing compiler"])

AC_CHECK_TOOL(NM, nm, false)

if test "x$maintainer" = "xyes"; then
  AC_CHECK_PROGS(AUTOCONF, autoconf, no)
  case "x$AUTOCONF" in
  xno|x|x:) AUTOCONF=no ;;
  *)
    AC_CACHE_CHECK(dnl
  whether $AUTOCONF${ACFLAGS:+ }$ACFLAGS works, libc_cv_autoconf_works, [dnl
    if (cd $srcdir; $AUTOCONF $ACFLAGS configure.ac > /dev/null 2>&1); then
      libc_cv_autoconf_works=yes
    else
      libc_cv_autoconf_works=no
    fi])
    test $libc_cv_autoconf_works = yes || AUTOCONF=no
    ;;
  esac
  if test "x$AUTOCONF" = xno; then
    aux_missing="$aux_missing autoconf"
  fi
else
  AUTOCONF=no
fi

test -n "$critic_missing" && AC_MSG_ERROR([
*** These critical programs are missing or too old:$critic_missing
*** Check the INSTALL file for required versions.])

test -n "$aux_missing" && AC_MSG_WARN([
*** These auxiliary programs are missing or incompatible versions:$aux_missing
*** some features will be disabled.
*** Check the INSTALL file for required versions.])

# if using special system headers, find out the compiler's sekrit
# header directory and add that to the list.  NOTE: Only does the right
# thing on a system that doesn't need fixincludes.  (Not presently a problem.)
if test -n "$sysheaders"; then
  SYSINCLUDES=-nostdinc
  for d in include include-fixed; do
    i=`$CC -print-file-name="$d"` && test "x$i" != x && test "x$i" != "x$d" &&
    SYSINCLUDES="$SYSINCLUDES -isystem $i"
  done
  SYSINCLUDES="$SYSINCLUDES \
-isystem `echo $sysheaders | sed 's/:/ -isystem /g'`"
  if test -n "$CXX"; then
    CXX_SYSINCLUDES=
    for cxxheaders in `$CXX -v -S -x c++ /dev/null -o /dev/null 2>&1 \
    | sed -n -e '1,/#include/d' -e 's/^ \(\/.*\/[cg]++\)/\1/p'`; do
      test "x$cxxheaders" != x &&
      CXX_SYSINCLUDES="$CXX_SYSINCLUDES -isystem $cxxheaders"
    done
  fi
fi
AC_SUBST(SYSINCLUDES)
AC_SUBST(CXX_SYSINCLUDES)

# Test if LD_LIBRARY_PATH contains the notation for the current directory
# since this would lead to problems installing/building glibc.
# LD_LIBRARY_PATH contains the current directory if one of the following
# is true:
# - one of the terminals (":" and ";") is the first or last sign
# - two terminals occur directly after each other
# - the path contains an element with a dot in it
AC_MSG_CHECKING(LD_LIBRARY_PATH variable)
changequote(,)dnl
case ${LD_LIBRARY_PATH} in
  [:\;]* | *[:\;] | *[:\;][:\;]* |  *[:\;]. | .[:\;]*| . | *[:\;].[:\;]* )
    ld_library_path_setting="contains current directory"
    ;;
  *)
    ld_library_path_setting="ok"
    ;;
esac
changequote([,])dnl
AC_MSG_RESULT($ld_library_path_setting)
if test "$ld_library_path_setting" != "ok"; then
AC_MSG_ERROR([
*** LD_LIBRARY_PATH shouldn't contain the current directory when
*** building glibc. Please change the environment variable
*** and run configure again.])
fi

AC_CACHE_CHECK(whether GCC supports -static-libgcc, libc_cv_gcc_static_libgcc, [dnl
if $CC -v -static-libgcc 2>&1 | grep 'unrecognized option.*static-libgcc' >/dev/null; then
  libc_cv_gcc_static_libgcc=
else
  libc_cv_gcc_static_libgcc=-static-libgcc
fi])
AC_SUBST(libc_cv_gcc_static_libgcc)

AC_PATH_PROG(BASH_SHELL, bash, no)

AC_PATH_PROG(PERL, perl, no)
if test "$PERL" != no &&
   (eval `$PERL -V:apiversion`; test `expr "$apiversion" \< 5` -ne 0); then
  PERL=no
fi
AC_PATH_PROG(INSTALL_INFO, install-info, no,
	     $PATH:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin)
AC_CHECK_PROG_VER(BISON, bison, --version,
		  [bison (GNU Bison) \([0-9]*\.[0-9.]*\)],
		  [2.7*|[3-9].*|[1-9][0-9]*],
		  BISON=no)

AC_CACHE_CHECK(for libc-friendly stddef.h, libc_cv_friendly_stddef, [dnl
AC_TRY_COMPILE(dnl
[#define __need_size_t
#define __need_wchar_t
#include <stddef.h>
#define __need_NULL
#include <stddef.h>], [size_t size; wchar_t wchar;
#ifdef offsetof
#error stddef.h ignored __need_*
#endif
if (&size == NULL || &wchar == NULL) abort ();],
	       libc_cv_friendly_stddef=yes,
	       libc_cv_friendly_stddef=no)])
if test $libc_cv_friendly_stddef = yes; then
  config_vars="$config_vars
override stddef.h = # The installed <stddef.h> seems to be libc-friendly."
fi

AC_CACHE_CHECK(whether we need to use -P to assemble .S files,
	       libc_cv_need_minus_P, [dnl
cat > conftest.S <<EOF
#include "confdefs.h"
/* Nothing whatsoever.  */
EOF
if AC_TRY_COMMAND(${CC-cc} $CPPFLAGS $ASFLAGS -c conftest.S 1>&AS_MESSAGE_LOG_FD); then
  libc_cv_need_minus_P=no
else
  libc_cv_need_minus_P=yes
fi
rm -f conftest*])
if test $libc_cv_need_minus_P = yes; then
  config_vars="$config_vars
asm-CPPFLAGS = -P # The assembler can't grok cpp's # line directives."
fi

AC_CACHE_CHECK(for .set assembler directive, libc_cv_asm_set_directive, [dnl
cat > conftest.s <<EOF
${libc_cv_dot_text}
foo:
.set glibc_conftest_frobozz,foo
.globl glibc_conftest_frobozz
EOF
# The alpha-dec-osf1 assembler gives only a warning for `.set'
# (but it doesn't work), so we must do a linking check to be sure.
cat > conftest1.c <<\EOF
extern int glibc_conftest_frobozz;
void _start() { glibc_conftest_frobozz = 1; }
EOF
if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \
	    -nostartfiles -nostdlib \
	    -o conftest conftest.s conftest1.c 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then
  libc_cv_asm_set_directive=yes
else
  libc_cv_asm_set_directive=no
fi
rm -f conftest*])
if test $libc_cv_asm_set_directive = yes; then
  AC_DEFINE(HAVE_ASM_SET_DIRECTIVE)
fi

AC_CACHE_CHECK(for assembler gnu_unique_object symbol type,
	       libc_cv_asm_unique_object, [dnl
cat > conftest.s <<EOF
${libc_cv_dot_text}
_sym:
.type _sym, %gnu_unique_object
EOF
if ${CC-cc} -c $ASFLAGS conftest.s 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then
  libc_cv_asm_unique_object=yes
else
  libc_cv_asm_unique_object=no
fi
rm -f conftest*])
if test $libc_cv_asm_unique_object = yes; then
  AC_DEFINE(HAVE_ASM_UNIQUE_OBJECT)
fi

AC_CACHE_CHECK(for .previous assembler directive,
	       libc_cv_asm_previous_directive, [dnl
cat > conftest.s <<EOF
.section foo_section
.previous
EOF
if AC_TRY_COMMAND(${CC-cc} -c $ASFLAGS conftest.s 1>&AS_MESSAGE_LOG_FD); then
  libc_cv_asm_previous_directive=yes
else
  libc_cv_asm_previous_directive=no
fi
rm -f conftest*])
if test $libc_cv_asm_previous_directive = yes; then
  AC_DEFINE(HAVE_ASM_PREVIOUS_DIRECTIVE)
else
  AC_CACHE_CHECK(for .popsection assembler directive,
		 libc_cv_asm_popsection_directive, [dnl
  cat > conftest.s <<EOF
.pushsection foo_section
.popsection
EOF
  if AC_TRY_COMMAND(${CC-cc} -c $ASFLAGS conftest.s 1>&AS_MESSAGE_LOG_FD); then
    libc_cv_asm_popsection_directive=yes
  else
    libc_cv_asm_popsection_directive=no
  fi
  rm -f conftest*])
  if test $libc_cv_asm_popsection_directive = yes; then
    AC_DEFINE(HAVE_ASM_POPSECTION_DIRECTIVE)
  fi
fi
AC_CACHE_CHECK(for .protected and .hidden assembler directive,
	       libc_cv_asm_protected_directive, [dnl
cat > conftest.s <<EOF
.protected foo
foo:
.hidden bar
bar:
EOF
if AC_TRY_COMMAND(${CC-cc} -c $ASFLAGS conftest.s 1>&AS_MESSAGE_LOG_FD); then
  libc_cv_asm_protected_directive=yes
else
  AC_MSG_ERROR(assembler support for symbol visibility is required)
fi
rm -f conftest*])

if test $libc_cv_asm_protected_directive = yes; then
  AC_CACHE_CHECK(whether __attribute__((visibility())) is supported,
		 libc_cv_visibility_attribute,
		 [cat > conftest.c <<EOF
		  int foo __attribute__ ((visibility ("hidden"))) = 1;
		  int bar __attribute__ ((visibility ("protected"))) = 1;
EOF
		  libc_cv_visibility_attribute=no
		  if AC_TRY_COMMAND(${CC-cc} -Werror -S conftest.c -o conftest.s 1>&AS_MESSAGE_LOG_FD); then
		    if grep '\.hidden.*foo' conftest.s >/dev/null; then
		      if grep '\.protected.*bar' conftest.s >/dev/null; then
			libc_cv_visibility_attribute=yes
		      fi
		    fi
		  fi
		  rm -f conftest.{c,s}
		 ])
  if test $libc_cv_visibility_attribute != yes; then
    AC_MSG_ERROR(compiler support for visibility attribute is required)
  fi
fi

if test $libc_cv_visibility_attribute = yes; then
  AC_CACHE_CHECK(linker support for protected data symbol,
		 libc_cv_protected_data,
		 [cat > conftest.c <<EOF
		  int bar __attribute__ ((visibility ("protected"))) = 1;
EOF
		  libc_cv_protected_data=no
		  if AC_TRY_COMMAND(${CC-cc} -nostdlib -nostartfiles -fPIC -shared conftest.c -o conftest.so); then
		    cat > conftest.c <<EOF
		    extern int bar;
		    int main (void) { return bar; }
EOF
		    if AC_TRY_COMMAND(${CC-cc} -nostdlib -nostartfiles conftest.c -o conftest conftest.so); then
		      libc_cv_protected_data=yes
		    fi
		  fi
		  rm -f conftest.*
		 ])
else
  libc_cv_protected_data=no
fi
AC_SUBST(libc_cv_protected_data)

if test $libc_cv_visibility_attribute = yes; then
  AC_CACHE_CHECK(for broken __attribute__((visibility())),
		 libc_cv_broken_visibility_attribute,
		 [cat > conftest.c <<EOF
		  int foo (int x);
		  int bar (int x) __asm__ ("foo") __attribute__ ((visibility ("hidden")));
		  int bar (int x) { return x; }
EOF
		  libc_cv_broken_visibility_attribute=yes
		  if AC_TRY_COMMAND(${CC-cc} -Werror -S conftest.c -o conftest.s 1>&AS_MESSAGE_LOG_FD); then
changequote(,)dnl
		    if grep '\.hidden[ 	_]foo' conftest.s >/dev/null; then
changequote([,])dnl
		      libc_cv_broken_visibility_attribute=no
		    fi
		  fi
		  rm -f conftest.c conftest.s
		 ])
  if test $libc_cv_broken_visibility_attribute = yes; then
    AC_MSG_ERROR(working compiler support for visibility attribute is required)
  fi
fi

AC_CACHE_CHECK(for broken __attribute__((alias())),
	       libc_cv_broken_alias_attribute,
	       [cat > conftest.c <<EOF
	       extern int foo (int x) __asm ("xyzzy");
	       int bar (int x) { return x; }
	       extern __typeof (bar) foo __attribute ((weak, alias ("bar")));
	       extern int dfoo;
	       extern __typeof (dfoo) dfoo __asm ("abccb");
	       int dfoo = 1;
EOF
	       libc_cv_broken_alias_attribute=yes
	       if AC_TRY_COMMAND(${CC-cc} -Werror -S conftest.c -o conftest.s 1>&AS_MESSAGE_LOG_FD); then
		 if grep 'xyzzy' conftest.s >/dev/null &&
		    grep 'abccb' conftest.s >/dev/null; then
		   libc_cv_broken_alias_attribute=no
		 fi
	       fi
	       rm -f conftest.c conftest.s
	       ])
if test $libc_cv_broken_alias_attribute = yes; then
  AC_MSG_ERROR(working alias attribute support required)
fi

if test $libc_cv_visibility_attribute = yes; then
  AC_CACHE_CHECK(whether to put _rtld_local into .sdata section,
		 libc_cv_have_sdata_section,
		 [echo "int i;" > conftest.c
		  libc_cv_have_sdata_section=no
		  if ${CC-cc} $LDFLAGS -fPIC -shared -Wl,--verbose conftest.c -o conftest.so 2>&1 \
		     | grep '\.sdata' >/dev/null; then
		    libc_cv_have_sdata_section=yes
		  fi
		  rm -f conftest.c conftest.so
		 ])
  if test $libc_cv_have_sdata_section = yes; then
    AC_DEFINE(HAVE_SDATA_SECTION)
  fi
fi

AC_CACHE_CHECK(for .preinit_array/.init_array/.fini_array support,
	       libc_cv_initfini_array, [dnl
LIBC_TRY_LINK_STATIC([
int foo (void) { return 1; }
int (*fp) (void) __attribute__ ((section (".init_array"))) = foo;
],
  [if $READELF -S conftest | fgrep INIT_ARRAY > /dev/null; then
    libc_cv_initfini_array=yes
  else
    libc_cv_initfini_array=no
  fi],
  [libc_cv_initfini_array=no])
])
if test $libc_cv_initfini_array != yes; then
  AC_MSG_ERROR([Need linker with .init_array/.fini_array support.])
fi

AC_CACHE_CHECK(whether to use .ctors/.dtors header and trailer,
	       libc_cv_ctors_header, [dnl
  libc_cv_ctors_header=yes
  LIBC_TRY_LINK_STATIC([
__attribute__ ((constructor)) void ctor (void) { asm (""); }
__attribute__ ((destructor))  void dtor (void) { asm (""); }
],
	      [dnl
      AS_IF([$READELF -WS conftest$ac_exeext | $AWK '
	{ gsub(/\@<:@ */, "@<:@") }
	$2 == ".ctors" || $2 == ".dtors" {
	  size = strtonum("0x" $6)
	  align = strtonum("0x" $NF)
	  seen@<:@$2@:>@ = 1
	  stub@<:@$2@:>@ = size == align * 2
	}
	END {
	  ctors_ok = !seen@<:@".ctors"@:>@ || stub@<:@".ctors"@:>@
	  dtors_ok = !seen@<:@".dtors"@:>@ || stub@<:@".dtors"@:>@
	  exit ((ctors_ok && dtors_ok) ? 0 : 1)
	}
      '], [libc_cv_ctors_header=no])
    ], [dnl
      AC_MSG_ERROR([missing __attribute__ ((constructor)) support??])
    ])
])
if test $libc_cv_ctors_header = no; then
  AC_DEFINE(NO_CTORS_DTORS_SECTIONS)
fi

AC_CACHE_CHECK(for libunwind-support in compiler,
	       libc_cv_cc_with_libunwind, [
  cat > conftest.c <<EOF
int main (void) { return 0; }
EOF
  if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS -static -o conftest \
     conftest.c -v 2>&1 >/dev/null | grep ' -lunwind ' >/dev/null; then
    libc_cv_cc_with_libunwind=yes
  else
    libc_cv_cc_with_libunwind=no
  fi
  rm -f conftest*])
AC_SUBST(libc_cv_cc_with_libunwind)
if test $libc_cv_cc_with_libunwind = yes; then
  AC_DEFINE(HAVE_CC_WITH_LIBUNWIND)
fi

LIBC_LINKER_FEATURE([-z nodelete], [-Wl,--enable-new-dtags,-z,nodelete],
		    [libc_cv_z_nodelete=yes],
		    [AC_MSG_ERROR(linker with -z nodelete support required)])

LIBC_LINKER_FEATURE([-z nodlopen], [-Wl,--enable-new-dtags,-z,nodlopen],
		    [libc_cv_z_nodlopen=yes],
		    [AC_MSG_ERROR(linker with -z nodlopen support required)])

LIBC_LINKER_FEATURE([-z initfirst], [-Wl,--enable-new-dtags,-z,initfirst],
		    [libc_cv_z_initfirst=yes],
		    [AC_MSG_ERROR(linker with -z initfirst support required)])

AC_CACHE_CHECK(for -Bgroup option,
	       libc_cv_Bgroup, [dnl
cat > conftest.c <<EOF
int _start (void) { return 42; }
EOF
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
			    -fPIC -shared -o conftest.so conftest.c
			    -Wl,-Bgroup -nostdlib 1>&AS_MESSAGE_LOG_FD])
then
  libc_cv_Bgroup=yes
else
  libc_cv_Bgroup=no
fi
rm -f conftest*])
AC_SUBST(libc_cv_Bgroup)

ASFLAGS_config=
AC_CACHE_CHECK(whether --noexecstack is desirable for .S files,
	       libc_cv_as_noexecstack, [dnl
cat > conftest.c <<EOF
void foo (void) { }
EOF
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS
		   -S -o conftest.s conftest.c 1>&AS_MESSAGE_LOG_FD]) \
   && grep .note.GNU-stack conftest.s >/dev/null \
   && AC_TRY_COMMAND([${CC-cc} $ASFLAGS -Wa,--noexecstack
		      -c -o conftest.o conftest.s 1>&AS_MESSAGE_LOG_FD])
then
  libc_cv_as_noexecstack=yes
else
  libc_cv_as_noexecstack=no
fi
rm -f conftest*])
if test $libc_cv_as_noexecstack = yes; then
  ASFLAGS_config="$ASFLAGS_config -Wa,--noexecstack"
fi
AC_SUBST(ASFLAGS_config)

AC_CACHE_CHECK(for -z combreloc,
	       libc_cv_z_combreloc, [dnl
cat > conftest.c <<EOF
extern int bar (int);
extern int mumble;
int foo (void) { return bar (mumble); }
EOF
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
			-fPIC -shared -o conftest.so conftest.c
			-nostdlib -nostartfiles
			-Wl,-z,combreloc 1>&AS_MESSAGE_LOG_FD])
then
dnl The following test is a bit weak.  We must use a tool which can test
dnl cross-platform since the gcc used can be a cross compiler.  Without
dnl introducing new options this is not easily doable.  Instead use a tool
dnl which always is cross-platform: readelf.  To detect whether -z combreloc
dnl look for a section named .rel.dyn.
  if $READELF -S conftest.so | grep '\.rel\(a\|\)\.dyn' > /dev/null; then
    libc_cv_z_combreloc=yes
  else
    libc_cv_z_combreloc=no
  fi
else
  libc_cv_z_combreloc=no
fi
rm -f conftest*])
if test "$libc_cv_z_combreloc" = yes; then
  AC_DEFINE(HAVE_Z_COMBRELOC)
fi
AC_SUBST(libc_cv_z_combreloc)

LIBC_LINKER_FEATURE([-z execstack], [-Wl,-z,execstack],
		    [libc_cv_z_execstack=yes], [libc_cv_z_execstack=no])
AC_SUBST(libc_cv_z_execstack)

AC_CACHE_CHECK(for -fpie, libc_cv_fpie, [dnl
LIBC_TRY_CC_OPTION([-fpie], [libc_cv_fpie=yes], [libc_cv_fpie=no])
])

AC_SUBST(libc_cv_fpie)

AC_CACHE_CHECK(for --hash-style option,
	       libc_cv_hashstyle, [dnl
cat > conftest.c <<EOF
int _start (void) { return 42; }
EOF
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
			    -fPIC -shared -o conftest.so conftest.c
			    -Wl,--hash-style=both -nostdlib 1>&AS_MESSAGE_LOG_FD])
then
  libc_cv_hashstyle=yes
else
  libc_cv_hashstyle=no
fi
rm -f conftest*])
AC_SUBST(libc_cv_hashstyle)

# The linker's default -shared behavior is good enough if it
# does these things that our custom linker scripts ensure that
# all allocated NOTE sections come first.
if test "$use_default_link" = default; then
  AC_CACHE_CHECK([for sufficient default -shared layout],
		  libc_cv_use_default_link, [dnl
  libc_cv_use_default_link=no
  cat > conftest.s <<\EOF
	  .section .note.a,"a",%note
	  .balign 4
	  .long 4,4,9
	  .string "GNU"
	  .string "foo"
	  .section .note.b,"a",%note
	  .balign 4
	  .long 4,4,9
	  .string "GNU"
	  .string "bar"
EOF
  if AC_TRY_COMMAND([dnl
  ${CC-cc} $ASFLAGS -shared -o conftest.so conftest.s 1>&AS_MESSAGE_LOG_FD]) &&
       ac_try=`$READELF -S conftest.so | sed -n \
	 ['${x;p;}
	  s/^ *\[ *[1-9][0-9]*\]  *\([^ ][^ ]*\)  *\([^ ][^ ]*\) .*$/\2 \1/
	  t a
	  b
	  : a
	  H']`
  then
    libc_seen_a=no libc_seen_b=no
    set -- $ac_try
    while test $# -ge 2 -a "$1" = NOTE; do
      case "$2" in
      .note.a) libc_seen_a=yes ;;
      .note.b) libc_seen_b=yes ;;
      esac
      shift 2
    done
    case "$libc_seen_a$libc_seen_b" in
    yesyes)
      libc_cv_use_default_link=yes
      ;;
    *)
      echo >&AS_MESSAGE_LOG_FD "\
$libc_seen_a$libc_seen_b from:
$ac_try"
      ;;
    esac
  fi
  rm -f conftest*])
  use_default_link=$libc_cv_use_default_link
fi

AC_CACHE_CHECK(linker output format, libc_cv_output_format, [dnl
if libc_cv_output_format=`
${CC-cc} -nostartfiles -nostdlib -Wl,--print-output-format 2>&AS_MESSAGE_LOG_FD`
then
  :
else
  libc_cv_output_format=
fi
test -n "$libc_cv_output_format" || libc_cv_output_format=unknown])
AC_SUBST(libc_cv_output_format)

AC_CACHE_CHECK(for -fno-toplevel-reorder -fno-section-anchors, libc_cv_fno_toplevel_reorder, [dnl
cat > conftest.c <<EOF
int foo;
EOF
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -S -fno-toplevel-reorder -fno-section-anchors
			    conftest.c 1>&AS_MESSAGE_LOG_FD])
then
  libc_cv_fno_toplevel_reorder=yes
else
  libc_cv_fno_toplevel_reorder=no
fi
rm -f conftest*])
if test $libc_cv_fno_toplevel_reorder = yes; then
  fno_unit_at_a_time="-fno-toplevel-reorder -fno-section-anchors"
else
  fno_unit_at_a_time=-fno-unit-at-a-time
fi
AC_SUBST(fno_unit_at_a_time)

AC_CACHE_CHECK(for -fstack-protector, libc_cv_ssp, [dnl
LIBC_TRY_CC_OPTION([$CFLAGS $CPPFLAGS -Werror -fstack-protector],
		   [libc_cv_ssp=yes],
		   [libc_cv_ssp=no])
])
AC_SUBST(libc_cv_ssp)

AC_CACHE_CHECK(for -fgnu89-inline, libc_cv_gnu89_inline, [dnl
cat > conftest.c <<EOF
int foo;
#ifdef __GNUC_GNU_INLINE__
main () { return 0;}
#else
#error
#endif
EOF
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -S -std=gnu99 -fgnu89-inline
			    -o conftest.s conftest.c 1>&AS_MESSAGE_LOG_FD])
then
  libc_cv_gnu89_inline=yes
else
  libc_cv_gnu89_inline=no
fi
rm -f conftest*])
if test $libc_cv_gnu89_inline = yes; then
  gnu89_inline=-fgnu89-inline
else
  gnu89_inline=
fi
AC_SUBST(gnu89_inline)

AC_CACHE_CHECK(whether cc puts quotes around section names,
	       libc_cv_have_section_quotes,
	       [cat > conftest.c <<EOF
		static const int foo
		__attribute__ ((section ("bar"))) = 1;
EOF
		if ${CC-cc} -S conftest.c -o conftest.s; then
		  if grep '\.section.*"bar"' conftest.s >/dev/null; then
		    libc_cv_have_section_quotes=yes
		  else
		    libc_cv_have_section_quotes=no
		  fi
		else
		  libc_cv_have_section_quotes=unknown
		fi
		rm -f conftest.{c,s}
		])
if test $libc_cv_have_section_quotes = yes; then
  AC_DEFINE(HAVE_SECTION_QUOTES)
fi

AC_CACHE_CHECK(for assembler .weak directive, libc_cv_asm_weak_directive,
	       [dnl
cat > conftest.s <<EOF
${libc_cv_dot_text}
.globl foo
foo:
.weak foo
.weak bar; bar = foo
EOF
if AC_TRY_COMMAND(${CC-cc} $ASFLAGS -c conftest.s 1>&AS_MESSAGE_LOG_FD); then
  libc_cv_asm_weak_directive=yes
else
  libc_cv_asm_weak_directive=no
fi
rm -f conftest*])

if test $libc_cv_asm_weak_directive = no; then
  AC_CACHE_CHECK(for assembler .weakext directive,
		 libc_cv_asm_weakext_directive,
		 [dnl
cat > conftest.s <<EOF
${libc_cv_dot_text}
.globl foo
foo:
.weakext bar foo
.weakext baz
.globl baz
baz:
EOF
  if AC_TRY_COMMAND(${CC-cc} $ASFLAGS -c conftest.s 1>&AS_MESSAGE_LOG_FD); then
    libc_cv_asm_weakext_directive=yes
  else
    libc_cv_asm_weakext_directive=no
  fi
  rm -f conftest*])

fi # no .weak

if test $libc_cv_asm_weak_directive = yes; then
  AC_DEFINE(HAVE_ASM_WEAK_DIRECTIVE)
elif test $libc_cv_asm_weakext_directive = yes; then
  AC_DEFINE(HAVE_ASM_WEAKEXT_DIRECTIVE)
fi

AC_CACHE_CHECK(for ld --no-whole-archive, libc_cv_ld_no_whole_archive, [dnl
cat > conftest.c <<\EOF
_start () {}
int __eh_pc;
__throw () {}
EOF
dnl No \ in command here because it ends up inside ''.
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
			    -nostdlib -nostartfiles -Wl,--no-whole-archive
			    -o conftest conftest.c 1>&AS_MESSAGE_LOG_FD]); then
  libc_cv_ld_no_whole_archive=yes
else
  libc_cv_ld_no_whole_archive=no
fi
rm -f conftest*])
if test $libc_cv_ld_no_whole_archive = no; then
  AC_MSG_ERROR([support for --no-whole-archive is needed])
fi

AC_CACHE_CHECK(for gcc -fexceptions, libc_cv_gcc_exceptions, [dnl
cat > conftest.c <<\EOF
_start () {}
int __eh_pc;
__throw () {}
EOF
dnl No \ in command here because it ends up inside ''.
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
			    -nostdlib -nostartfiles -fexceptions
			    -o conftest conftest.c 1>&AS_MESSAGE_LOG_FD]); then
  libc_cv_gcc_exceptions=yes
else
  libc_cv_gcc_exceptions=no
fi
rm -f conftest*])
if test $libc_cv_gcc_exceptions = yes; then
  exceptions=-fexceptions
fi
AC_SUBST(exceptions)dnl

AC_CACHE_CHECK(for __builtin_memset, libc_cv_gcc_builtin_memset, [dnl
cat > conftest.c <<\EOF
void zero (void *x)
{
  __builtin_memset (x, 0, 1000);
}
EOF
dnl
if AC_TRY_COMMAND([${CC-cc} -O3 -S conftest.c -o - | fgrep "memset" > /dev/null]);
then
  libc_cv_gcc_builtin_memset=no
else
  libc_cv_gcc_builtin_memset=yes
fi
rm -f conftest* ])
if test "$libc_cv_gcc_builtin_memset" = yes ; then
  AC_DEFINE(HAVE_BUILTIN_MEMSET)
fi

AC_CACHE_CHECK(for redirection of built-in functions, libc_cv_gcc_builtin_redirection, [dnl
cat > conftest.c <<\EOF
extern char *strstr (const char *, const char *) __asm ("my_strstr");
char *foo (const char *a, const char *b)
{
  return __builtin_strstr (a, b);
}
EOF
dnl
if AC_TRY_COMMAND([${CC-cc} -O3 -S conftest.c -o - | fgrep "my_strstr" > /dev/null]);
then
  libc_cv_gcc_builtin_redirection=yes
else
  libc_cv_gcc_builtin_redirection=no
fi
rm -f conftest* ])
if test "$libc_cv_gcc_builtin_redirection" = no; then
  AC_MSG_ERROR([support for the symbol redirection needed])
fi

dnl Check whether the compiler supports the __thread keyword.
AC_CACHE_CHECK([for __thread], libc_cv_gcc___thread,
[cat > conftest.c <<\EOF
__thread int a = 42;
EOF
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c >&AS_MESSAGE_LOG_FD]); then
  libc_cv_gcc___thread=yes
else
  libc_cv_gcc___thread=no
fi
rm -f conftest*])
if test "$libc_cv_gcc___thread" = no; then
  AC_MSG_ERROR([support for the __thread keyword is required])
fi

dnl Check whether the compiler supports the tls_model attribute.
AC_CACHE_CHECK([for tls_model attribute], libc_cv_gcc_tls_model_attr, [dnl
cat > conftest.c <<\EOF
extern __thread int a __attribute__((tls_model ("initial-exec")));
EOF
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -S -Werror conftest.c >&AS_MESSAGE_LOG_FD]); then
  libc_cv_gcc_tls_model_attr=yes
else
  libc_cv_gcc_tls_model_attr=no
fi
rm -f conftest*])
if test "$libc_cv_gcc_tls_model_attr" = no; then
  AC_MSG_ERROR([support for the tls_model attribute is required])
fi

dnl Determine how to disable generation of FMA instructions.
AC_CACHE_CHECK([for compiler option to disable generation of FMA instructions],
	       libc_cv_cc_nofma, [dnl
libc_cv_cc_nofma=
for opt in -ffp-contract=off -mno-fused-madd; do
  LIBC_TRY_CC_OPTION([$opt], [libc_cv_cc_nofma=$opt; break])
done])
AC_SUBST(libc_cv_cc_nofma)

if test -n "$submachine"; then
  AC_CACHE_CHECK([for compiler option for CPU variant],
		 libc_cv_cc_submachine, [dnl
  libc_cv_cc_submachine=no
  for opt in "-march=$submachine" "-mcpu=$submachine"; do
    LIBC_TRY_CC_OPTION([$opt], [
      libc_cv_cc_submachine="$opt"
      break], [])
  done])
  if test "x$libc_cv_cc_submachine" = xno; then
    AC_MSG_ERROR([${CC-cc} does not support $submachine])
  fi
fi
AC_SUBST(libc_cv_cc_submachine)

AC_CACHE_CHECK(if $CC accepts -fno-tree-loop-distribute-patterns with \
__attribute__ ((__optimize__)), libc_cv_cc_loop_to_function, [dnl
cat > conftest.c <<EOF
void
__attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns")))
foo (void) {}
EOF
libc_cv_cc_loop_to_function=no
if AC_TRY_COMMAND([${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c])
then
  libc_cv_cc_loop_to_function=yes
fi
rm -f conftest*])
if test $libc_cv_cc_loop_to_function = yes; then
  AC_DEFINE(HAVE_CC_INHIBIT_LOOP_TO_LIBCALL)
fi
AC_SUBST(libc_cv_cc_loop_to_function)

dnl Check whether we have the gd library available.
AC_MSG_CHECKING(for libgd)
if test "$with_gd" != "no"; then
  old_CFLAGS="$CFLAGS"
  CFLAGS="$CFLAGS $libgd_include"
  old_LDFLAGS="$LDFLAGS"
  LDFLAGS="$LDFLAGS $libgd_ldflags"
  old_LIBS="$LIBS"
  LIBS="$LIBS -lgd -lpng -lz -lm"
  AC_TRY_LINK([#include <gd.h>], [gdImagePng (0, 0)], LIBGD=yes, LIBGD=no)
  CFLAGS="$old_CFLAGS"
  LDFLAGS="$old_LDFLAGS"
  LIBS="$old_LIBS"
else
  LIBGD=no
fi
AC_MSG_RESULT($LIBGD)
AC_SUBST(LIBGD)

# SELinux detection
if test x$with_selinux = xno ; then
  have_selinux=no;
else
  # See if we have the SELinux library
  AC_CHECK_LIB(selinux, is_selinux_enabled,
	       have_selinux=yes, have_selinux=no)
  if test x$with_selinux = xyes ; then
    if test x$have_selinux = xno ; then
      AC_MSG_ERROR([SELinux explicitly required, but SELinux library not found])
    fi
  fi
fi
# Check if we're building with SELinux support.
if test "x$have_selinux" = xyes; then
  AC_DEFINE(HAVE_SELINUX, 1, [SELinux support])

  # See if we have the libaudit library
  AC_CHECK_LIB(audit, audit_log_user_avc_message,
	       have_libaudit=yes, have_libaudit=no)
  if test "x$have_libaudit" = xyes; then
    AC_DEFINE(HAVE_LIBAUDIT, 1, [SELinux libaudit support])
  fi
  AC_SUBST(have_libaudit)

  # See if we have the libcap library
  AC_CHECK_LIB(cap, cap_init, have_libcap=yes, have_libcap=no)
  if test "x$have_libcap" = xyes; then
    AC_DEFINE(HAVE_LIBCAP, 1, [SELinux libcap support])
  fi
  AC_SUBST(have_libcap)
fi
AC_SUBST(have_selinux)

dnl check for the size of 'long double'.
AC_CHECK_SIZEOF(long double, 0)
sizeof_long_double=$ac_cv_sizeof_long_double
AC_SUBST(sizeof_long_double)

CPPUNDEFS=
dnl Check for silly hacked compilers predefining _FORTIFY_SOURCE.
dnl Since we are building the implementations of the fortified functions here,
dnl having the macro defined interacts very badly.
AC_CACHE_CHECK([for _FORTIFY_SOURCE predefine], libc_cv_predef_fortify_source,
[AC_TRY_COMPILE([], [
#ifdef _FORTIFY_SOURCE
# error bogon
#endif],
		[libc_cv_predef_fortify_source=no],
		[libc_cv_predef_fortify_source=yes])])
if test $libc_cv_predef_fortify_source = yes; then
  CPPUNDEFS="${CPPUNDEFS:+$CPPUNDEFS }-U_FORTIFY_SOURCE"
fi
AC_SUBST(CPPUNDEFS)

dnl Check for silly hacked compilers inserting -fstack-protector.
dnl This breaks badly for the early startup code we compile, since
dnl the compiled code can refer to a magic machine-dependent location
dnl for the canary value before we have sufficient setup for that to
dnl work.  It's also questionable to build all of libc with this flag
dnl even when you're doing that for most applications you build, since
dnl libc's code is so heavily-used and performance-sensitive.  If we
dnl ever really want to make that work, it should be enabled explicitly
dnl in the libc build, not inherited from implicit compiler settings.
AC_CACHE_CHECK([whether $CC implicitly enables -fstack-protector],
	       libc_cv_predef_stack_protector, [
AC_TRY_COMPILE([extern void foobar (char *);],
	       [char large_array[2048]; foobar (large_array);], [
libc_undefs=`$NM -u conftest.o |
  LC_ALL=C $AWK '$1 == "U" { print $2 | "sort -u"; next } { exit(1) }' \
    2>&AS_MESSAGE_LOG_FD` || {
  AC_MSG_ERROR([confusing output from $NM -u])
}
echo >&AS_MESSAGE_LOG_FD "libc_undefs='$libc_undefs'"
# On some architectures, there are architecture-specific undefined
# symbols (resolved by the linker), so filter out unknown symbols.
# This will fail to produce the correct result if the compiler
# defaults to -fstack-protector but this produces an undefined symbol
# other than __stack_chk_fail.  However, compilers like that have not
# been encountered in practice.
libc_undefs=`echo "$libc_undefs" | egrep '^(foobar|__stack_chk_fail)$'`
case "$libc_undefs" in
foobar) libc_cv_predef_stack_protector=no ;;
'__stack_chk_fail
foobar') libc_cv_predef_stack_protector=yes ;;
*) AC_MSG_ERROR([unexpected symbols in test: $libc_undefs]) ;;
esac],
	       [AC_MSG_ERROR([test compilation failed])])
])
libc_extra_cflags=
if test $libc_cv_predef_stack_protector = yes; then
  libc_extra_cflags="$libc_extra_cflags -fno-stack-protector"
fi
libc_extra_cppflags=

# Some linkers on some architectures support __ehdr_start but with
# bugs.  Make sure usage of it does not create relocations in the
# output (as the linker should resolve them all for us).
AC_CACHE_CHECK([whether the linker provides working __ehdr_start],
	       libc_cv_ehdr_start, [
old_CFLAGS="$CFLAGS"
old_LDFLAGS="$LDFLAGS"
old_LIBS="$LIBS"
CFLAGS="$CFLAGS -fPIC"
LDFLAGS="$LDFLAGS -nostdlib -nostartfiles -shared"
LIBS=
AC_LINK_IFELSE([AC_LANG_SOURCE([
typedef struct {
  char foo;
  long val;
} Ehdr;
extern const Ehdr __ehdr_start __attribute__ ((visibility ("hidden")));
long ehdr (void) { return __ehdr_start.val; }
])],
	       [if $READELF -r conftest | fgrep __ehdr_start >/dev/null; then
		  libc_cv_ehdr_start=broken
		else
		  libc_cv_ehdr_start=yes
		fi], [libc_cv_ehdr_start=no])
CFLAGS="$old_CFLAGS"
LDFLAGS="$old_LDFLAGS"
LIBS="$old_LIBS"
])
if test "$libc_cv_ehdr_start" = yes; then
  AC_DEFINE([HAVE_EHDR_START])
elif test "$libc_cv_ehdr_start" = broken; then
  AC_MSG_WARN([linker is broken -- you should upgrade])
fi

AC_CACHE_CHECK(for __builtin_trap with no external dependencies,
	       libc_cv_builtin_trap, [dnl
libc_cv_builtin_trap=no
AC_TRY_COMPILE([], [__builtin_trap ()], [
libc_undefs=`$NM -u conftest.o |
  LC_ALL=C $AWK '$1 == "U" { print $2 | "sort -u"; next } { exit(1) }' \
    2>&AS_MESSAGE_LOG_FD` || {
  AC_MSG_ERROR([confusing output from $NM -u])
}
echo >&AS_MESSAGE_LOG_FD "libc_undefs='$libc_undefs'"
if test -z "$libc_undefs"; then
  libc_cv_builtin_trap=yes
fi])])
if test $libc_cv_builtin_trap = yes; then
  AC_DEFINE([HAVE_BUILTIN_TRAP])
fi

### End of automated tests.
### Now run sysdeps configure fragments.

# They also can set these variables.
use_ldconfig=no
ldd_rewrite_script=no
libc_cv_sysconfdir=$sysconfdir
libc_cv_localstatedir=$localstatedir
libc_cv_gcc_unwind_find_fde=no
libc_cv_idn=no

# Iterate over all the sysdep directories we will use, running their
# configure fragments.
for dir in $sysnames; do
  case $dir in
    /*) dest=$dir ;;
    *)  dest=$srcdir/$dir ;;
  esac
  if test -r $dest/configure; then
    AC_MSG_RESULT(running configure fragment for $dir)
    . $dest/configure
  fi
done

if test x"$build_mathvec" = xnotset; then
  build_mathvec=no
fi
LIBC_CONFIG_VAR([build-mathvec], [$build_mathvec])

AC_SUBST(libc_extra_cflags)
AC_SUBST(libc_extra_cppflags)

if test x$libc_cv_gcc_unwind_find_fde = xyes; then
  AC_DEFINE(EXPORT_UNWIND_FIND_FDE)
fi
AC_SUBST(libc_cv_gcc_unwind_find_fde)

# A sysdeps configure fragment can reset this if IFUNC is not actually
# usable even though the assembler knows how to generate the symbol type.
if test x"$libc_cv_ld_gnu_indirect_function" = xyes; then
  AC_DEFINE(HAVE_IFUNC)
fi

# This is far from the AC_ARG_ENABLE that sets it so that a sysdeps
# configure fragment can override the value to prevent this AC_DEFINE.
AC_SUBST(use_nscd)
if test "x$use_nscd" != xno; then
  AC_DEFINE([USE_NSCD])
fi
if test "x$build_nscd" = xdefault; then
  build_nscd=$use_nscd
fi

# Test for old glibc 2.0.x headers so that they can be removed properly
# Search only in includedir.
AC_MSG_CHECKING(for old glibc 2.0.x headers)
if eval test -f "${includedir}/elfclass.h" -a -f "${includedir}/fcntlbits.h"
then
  old_glibc_headers=yes
else
  old_glibc_headers=no
fi
AC_MSG_RESULT($old_glibc_headers)
if test ${old_glibc_headers} = yes; then
  AC_MSG_WARN(*** During \"make install\" old headers from glibc 2.0.x will)
  AC_MSG_WARN(*** be removed.)
fi
AC_SUBST(old_glibc_headers)

AC_SUBST(libc_cv_slibdir)
AC_SUBST(libc_cv_rtlddir)
AC_SUBST(libc_cv_localedir)
AC_SUBST(libc_cv_sysconfdir)
AC_SUBST(libc_cv_localstatedir)
AC_SUBST(libc_cv_rootsbindir)
AC_SUBST(libc_cv_forced_unwind)

if test x$use_ldconfig = xyes; then
  AC_DEFINE(USE_LDCONFIG)
fi
AC_SUBST(use_ldconfig)
AC_SUBST(ldd_rewrite_script)

AC_SUBST(static)
AC_SUBST(shared)

AC_CACHE_CHECK([whether -fPIC is default], libc_cv_pic_default,
[libc_cv_pic_default=yes
cat > conftest.c <<EOF
#if defined __PIC__ || defined __pic__ || defined PIC || defined pic
# error PIC is default.
#endif
EOF
if eval "${CC-cc} -S conftest.c 2>&AS_MESSAGE_LOG_FD 1>&AS_MESSAGE_LOG_FD"; then
  libc_cv_pic_default=no
fi
rm -f conftest.*])
AC_SUBST(libc_cv_pic_default)

AC_CACHE_CHECK([whether -fPIE is default], libc_cv_pie_default,
[libc_cv_pie_default=yes
cat > conftest.c <<EOF
#if defined __PIE__ || defined __pie__ || defined PIE || defined pie
# error PIE is default.
#endif
EOF
if eval "${CC-cc} -S conftest.c 2>&AS_MESSAGE_LOG_FD 1>&AS_MESSAGE_LOG_FD"; then
  libc_cv_pie_default=no
fi
rm -f conftest.*])
AC_SUBST(libc_cv_pie_default)

AC_SUBST(profile)
AC_SUBST(static_nss)

AC_SUBST(DEFINES)

dnl See sysdeps/mach/configure.ac for this variable.
AC_SUBST(mach_interface_list)

VERSION=`sed -n -e 's/^#define VERSION "\([^"]*\)"/\1/p' < $srcdir/version.h`
RELEASE=`sed -n -e 's/^#define RELEASE "\([^"]*\)"/\1/p' < $srcdir/version.h`
AC_SUBST(VERSION)
AC_SUBST(RELEASE)

AC_CONFIG_FILES([config.make Makefile])
AC_CONFIG_COMMANDS([default],[[
case $CONFIG_FILES in *config.make*)
echo "$config_vars" >> config.make;;
esac
test -d bits || mkdir bits]],[[config_vars='$config_vars']])
AC_OUTPUT