-m4_copy([_AC_PREREQ], [AC_PREREQ])
-
-ifelse(m4_PACKAGE_VERSION, [2.59], [
-
-# _AC_OUTPUT_SUBDIRS
-# ------------------
-# This is a subroutine of AC_OUTPUT, but it does not go into
-# config.status, rather, it is called after running config.status.
-m4_define([_AC_OUTPUT_SUBDIRS],
-[
-#
-# CONFIG_SUBDIRS section, as fixed in confsubdir.m4.
-#
-if test "$no_recursion" != yes; then
-
- # Remove --cache-file and --srcdir arguments so they do not pile up.
- ac_sub_configure_args=
- ac_prev=
- eval "set x $ac_configure_args"
- shift
- for ac_arg
- do
- if test -n "$ac_prev"; then
- ac_prev=
- continue
- fi
- case $ac_arg in
- -cache-file | --cache-file | --cache-fil | --cache-fi \
- | --cache-f | --cache- | --cache | --cach | --cac | --ca | --c)
- ac_prev=cache_file ;;
- -cache-file=* | --cache-file=* | --cache-fil=* | --cache-fi=* \
- | --cache-f=* | --cache-=* | --cache=* | --cach=* | --cac=* | --ca=* \
- | --c=*)
- ;;
- --config-cache | -C)
- ;;
- -srcdir | --srcdir | --srcdi | --srcd | --src | --sr)
- ac_prev=srcdir ;;
- -srcdir=* | --srcdir=* | --srcdi=* | --srcd=* | --src=* | --sr=*)
- ;;
- -prefix | --prefix | --prefi | --pref | --pre | --pr | --p)
- ac_prev=prefix ;;
- -prefix=* | --prefix=* | --prefi=* | --pref=* | --pre=* | --pr=* | --p=*)
- ;;
- *)
- case $ac_arg in
- *\'*) ac_arg=`echo "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
- esac
- ac_sub_configure_args="$ac_sub_configure_args '$ac_arg'" ;;
- esac
- done
-
- # Always prepend --prefix to ensure using the same prefix
- # in subdir configurations.
- ac_arg="--prefix=$prefix"
- case $ac_arg in
- *\'*) ac_arg=`echo "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
- esac
- ac_sub_configure_args="$ac_arg $ac_sub_configure_args"
-
- ac_popdir=`pwd`
- for ac_dir in : $subdirs; do test "x$ac_dir" = x: && continue
-
- # Do not complain, so a configure script can configure whichever
- # parts of a large source tree are present.
- test -d "$srcdir/$ac_dir" || continue
-
- AC_MSG_NOTICE([configuring in $ac_dir])
- AS_MKDIR_P(["$ac_dir"])
- _AC_SRCPATHS(["$ac_dir"])
-
- cd "$ac_dir"
-
- # Check for guested configure; otherwise get Cygnus style configure.
- if test -f "$ac_srcdir/configure.gnu"; then
- ac_sub_configure=$ac_srcdir/configure.gnu
- elif test -f "$ac_srcdir/configure"; then
- ac_sub_configure=$ac_srcdir/configure
- elif test -f "$ac_srcdir/configure.in"; then
- # This should be Cygnus configure.
- ac_sub_configure=$ac_aux_dir/configure
- else
- AC_MSG_WARN([no configuration information is in $ac_dir])
- ac_sub_configure=
- fi
-
- # The recursion is here.
- if test -n "$ac_sub_configure"; then
- # Make the cache file name correct relative to the subdirectory.
- case $cache_file in
- [[\\/]]* | ?:[[\\/]]* ) ac_sub_cache_file=$cache_file ;;
- *) # Relative path.
- ac_sub_cache_file=$ac_top_builddir$cache_file ;;
- esac
-
- AC_MSG_NOTICE([running $SHELL $ac_sub_configure $ac_sub_configure_args --cache-file=$ac_sub_cache_file --srcdir=$ac_srcdir])
- # The eval makes quoting arguments work.
- eval "\$SHELL \"\$ac_sub_configure\" $ac_sub_configure_args \
- --cache-file=\"\$ac_sub_cache_file\" --srcdir=\"\$ac_srcdir\"" ||
- AC_MSG_ERROR([$ac_sub_configure failed for $ac_dir])
- fi
-
- cd "$ac_popdir"
- done
-fi
-])# _AC_OUTPUT_SUBDIRS
+m4_copy_force([_AC_PREREQ], [AC_PREREQ])
+
+
+dnl Ensure exactly this Autoconf version is used
+m4_ifndef([_GCC_AUTOCONF_VERSION],
+ [m4_define([_GCC_AUTOCONF_VERSION], [2.64])])
+
+dnl Test for the exact version when AC_INIT is expanded.
+dnl This allows to update the tree in steps (for testing)
+dnl by putting
+dnl m4_define([_GCC_AUTOCONF_VERSION], [X.Y])
+dnl in configure.ac before AC_INIT,
+dnl without rewriting this file.
+dnl Or for updating the whole tree at once with the definition above.
+AC_DEFUN([_GCC_AUTOCONF_VERSION_CHECK],
+[m4_if(m4_defn([_GCC_AUTOCONF_VERSION]),
+ m4_defn([m4_PACKAGE_VERSION]), [],
+ [m4_fatal([Please use exactly Autoconf ]_GCC_AUTOCONF_VERSION[ instead of ]m4_defn([m4_PACKAGE_VERSION])[.])])
+])
+m4_define([AC_INIT], m4_defn([AC_INIT])[
+_GCC_AUTOCONF_VERSION_CHECK