acinclude.m4 (gcc_AC_CHECK_PROG_VER): Remove.

gcc:
2007-06-14  Paolo Bonzini  <bonzini@gnu.org>

        * acinclude.m4 (gcc_AC_CHECK_PROG_VER): Remove.
        * aclocal.m4: Regenerate.
        * configure.ac: Use ACX_PROG_CC_WARNING_OPTS,
        ACX_PROG_CC_WARNINGS_ARE_ERRORS,
        ACX_PROG_CC_WARNING_ALMOST_PEDANTIC, ACX_CHECK_PROG_VER.
	* configure: Regenerate.
        * Makefile.in (LOOSE_WARN): Subst loose_warn.

        * Makefile.in (quickstrap): Build libgcc too.

libiberty:
2007-06-14  Paolo Bonzini  <bonzini@gnu.org>

        * aclocal.m4: Include config/warnings.m4.
        * configure.ac: Use ACX_PROG_CC_WARNING_OPTS.
	* configure: Regenerate.

config:
2007-06-14  Paolo Bonzini  <bonzini@gnu.org>

        * acx.m4 (ACX_CHECK_PROG_VER): Remove duplicate lines.

From-SVN: r125700

12 files changed, 220 insertions, 374 deletions

diff --git a/config/ChangeLog b/config/ChangeLog
index 2bf1f1e3706..af27fc69396 100644
--- a/config/ChangeLog
+++ b/config/ChangeLog
@@ -1,3 +1,7 @@
+2007-06-14  Paolo Bonzini  <bonzini@gnu.org>
+
+	* acx.m4 (ACX_CHECK_PROG_VER): Remove duplicate lines.
+
 2007-06-04  Olivier Hainque  <hainque@adacore.com>
 
 	* mh-ppc-aix: Add default ADAFLAGS to BOOT_ADAFLAGS.
diff --git a/config/acx.m4 b/config/acx.m4
index bbe7b5e06fb..a70d4077c33 100644
--- a/config/acx.m4
+++ b/config/acx.m4
@@ -540,10 +540,6 @@ AC_DEFUN([ACX_CHECK_PROG_VER],[
                       $5)  gcc_cv_prog_$2_modern=yes;;
                       *)   gcc_cv_prog_$2_modern=no;;
                     esac]
-
-                    if test $gcc_cv_prog_$2_modern = no; then
-                      $1="${CONFIG_SHELL-/bin/sh} $ac_aux_dir/missing $2"
-                    fi
                    ])
   else
     gcc_cv_prog_$2_modern=no
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2f6576bc33e..723786c3152 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,17 @@
 2007-06-14  Paolo Bonzini  <bonzini@gnu.org>
 
+	* acinclude.m4 (gcc_AC_CHECK_PROG_VER): Remove.
+	* aclocal.m4: Regenerate.
+	* configure.ac: Use ACX_PROG_CC_WARNING_OPTS,
+	ACX_PROG_CC_WARNINGS_ARE_ERRORS,
+	ACX_PROG_CC_WARNING_ALMOST_PEDANTIC, ACX_CHECK_PROG_VER.
+	* configure: Regenerate.
+        * Makefile.in (LOOSE_WARN): Subst loose_warn.
+
+        * Makefile.in (quickstrap): Build libgcc too.
+
+2007-06-14  Paolo Bonzini  <bonzini@gnu.org>
+
 	* configure.ac: Add --enable-checking=df.  Explicitly mention that
 	the variables are initialized as for "release".
 	* df-core.c: Use it.
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index bb250f83372..040007e9751 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -31,10 +31,6 @@
 # "all.cross" to build a cross compiler.
 all: @ALL@
 
-# Provide quickstrap as a target that people can type into the gcc directory,
-# and that fails if you're not into it.
-quickstrap: all
-
 # Depend on this to specify a phony target portably.
 force:
 
@@ -83,22 +79,27 @@ abs_docdir = @abs_srcdir@/doc
 
 # Top build directory for this package, relative to here.
 top_builddir = .
+
 # objdir is set by configure.
 # It's normally the absolute path to the current directory.
 objdir = @objdir@
 
 host_subdir=@host_subdir@
 build_subdir=@build_subdir@
+target_subdir=@target_subdir@
 build_libsubdir=@build_libsubdir@
 
+# Top build directory for the "Cygnus tree", relative to $(top_builddir).
 ifeq ($(host_subdir),.)
-build_objdir := ../$(build_subdir)
-build_libobjdir := ../$(build_libsubdir)
+toplevel_builddir := ..
 else
-build_objdir := ../../$(build_subdir)
-build_libobjdir := ../../$(build_libsubdir)
+toplevel_builddir := ../..
 endif
 
+build_objdir := $(toplevel_builddir)/$(build_subdir)
+build_libobjdir := $(toplevel_builddir)/$(build_libsubdir)
+target_objdir := $(toplevel_builddir)/$(target_subdir)
+
 # --------
 # Defined vpaths
 # --------
@@ -166,7 +167,7 @@ coverageexts = .{gcda,gcno}
 # apply to the back end and the C front end, which may be compiled
 # with other compilers.
 # CXX_COMPAT_WARN are C++ source compatibility warnings.
-LOOSE_WARN = -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes
+LOOSE_WARN = @loose_warn@
 STRICT_WARN = @strict_warn@
 CXX_COMPAT_WARN = @cxx_compat_warn@
 
@@ -1424,6 +1425,11 @@ config.status: $(srcdir)/configure $(srcdir)/config.gcc
 # UNSORTED
 # --------
 
+# Provide quickstrap as a target that people can type into the gcc directory,
+# and that fails if you're not into it.
+quickstrap: all
+	cd $(toplevel_builddir) && $(MAKE) all-target-libgcc
+
 all.internal: start.encap rest.encap doc
 # This is what to compile if making a cross-compiler.
 all.cross: native gcc-cross$(exeext) cpp$(exeext) specs \
diff --git a/gcc/acinclude.m4 b/gcc/acinclude.m4
index ec1931ce398..70322c75e6b 100644
--- a/gcc/acinclude.m4
+++ b/gcc/acinclude.m4
@@ -295,34 +295,6 @@ if test $gcc_cv_func_mmap_anon = yes; then
 fi
 ])
 
-dnl Locate a program and check that its version is acceptable.
-dnl AC_PROG_CHECK_VER(var, name, version-switch,
-dnl                  version-extract-regexp, version-glob)
-AC_DEFUN([gcc_AC_CHECK_PROG_VER],
-[AC_REQUIRE([gcc_AC_BUILD_EXEEXT])
-AC_CHECK_PROG([$1], [$2], [$2])
-if test -n "[$]$1"; then
-  # Found it, now check the version.
-  AC_CACHE_CHECK(for modern $2, gcc_cv_prog_$2_modern,
-[changequote(<<,>>)dnl
-  ac_prog_version=`<<$>>$1 $3 2>&1 |
-                   sed -n 's/^.*patsubst(<<$4>>,/,\/).*$/\1/p'`
-changequote([,])dnl
-  echo "configure:__oline__: version of $2 is $ac_prog_version" >&AS_MESSAGE_LOG_FD
-changequote(<<,>>)dnl
-  case $ac_prog_version in
-    '')     gcc_cv_prog_$2_modern=no;;
-    <<$5>>)
-            gcc_cv_prog_$2_modern=yes;;
-    *)      gcc_cv_prog_$2_modern=no;;
-  esac
-changequote([,])dnl
-])
-else
-  gcc_cv_prog_$2_modern=no
-fi
-])
-
 dnl Determine if enumerated bitfields are unsigned.   ISO C says they can 
 dnl be either signed or unsigned.
 dnl
diff --git a/gcc/aclocal.m4 b/gcc/aclocal.m4
index 1a71985f8c0..b89f4fa3766 100644
--- a/gcc/aclocal.m4
+++ b/gcc/aclocal.m4
@@ -101,4 +101,5 @@ m4_include([../config/lib-ld.m4])
 m4_include([../config/lib-link.m4])
 m4_include([../config/lib-prefix.m4])
 m4_include([../config/progtest.m4])
+m4_include([../config/warnings.m4])
 m4_include([acinclude.m4])
diff --git a/gcc/configure b/gcc/configure
index 2b435d4d49c..5900d2083d1 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -309,7 +309,7 @@ ac_includes_default="\
 # include <unistd.h>
 #endif"
 
-ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS build build_cpu build_vendor build_os host host_cpu host_vendor host_os target target_cpu target_vendor target_os target_noncanonical build_libsubdir build_subdir host_subdir target_subdir GENINSRC CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT NO_MINUS_C_MINUS_O OUTPUT_OPTION CPP EGREP strict_warn cxx_compat_warn warn_cflags nocommon_flag TREEBROWSER valgrind_path valgrind_path_defines valgrind_command coverage_flags enable_multilib enable_decimal_float enable_shared TARGET_SYSTEM_ROOT TARGET_SYSTEM_ROOT_DEFINE CROSS_SYSTEM_HEADER_DIR onestep datarootdir docdir htmldir SET_MAKE AWK LN_S LN RANLIB ac_ct_RANLIB ranlib_flags INSTALL INSTALL_PROGRAM INSTALL_DATA make_compare_target have_mktemp_command MAKEINFO BUILD_INFO GENERATED_MANPAGES FLEX BISON NM AR COLLECT2_LIBS GNAT_LIBEXC LDEXP_LIB TARGET_GETGROUPS_T LIBICONV LTLIBICONV LIBICONV_DEP manext objext gthread_flags extra_modes_file extra_opt_files USE_NLS LIBINTL LIBINTL_DEP INCINTL XGETTEXT GMSGFMT POSUB CATALOGS DATADIRNAME INSTOBJEXT GENCAT CATOBJEXT host_cc_for_libada CROSS ALL SYSTEM_HEADER_DIR inhibit_libc CC_FOR_BUILD BUILD_CFLAGS STMP_FIXINC STMP_FIXPROTO collect2 gcc_cv_as ORIGINAL_AS_FOR_TARGET gcc_cv_ld ORIGINAL_LD_FOR_TARGET gcc_cv_nm ORIGINAL_NM_FOR_TARGET gcc_cv_objdump libgcc_visibility GGC zlibdir zlibinc MAINT gcc_tooldir dollar slibdir objdir subdirs srcdir all_compilers all_gtfiles all_lang_makefrags all_lang_makefiles all_languages all_selected_languages build_exeext build_install_headers_dir build_xm_file_list build_xm_include_list build_xm_defines check_languages cpp_install_dir xmake_file tmake_file extra_gcc_objs extra_headers_list extra_objs extra_parts extra_passes extra_programs float_h_file gcc_config_arguments gcc_gxx_include_dir host_exeext host_xm_file_list host_xm_include_list host_xm_defines out_host_hook_obj install lang_opt_files lang_specs_files lang_tree_files local_prefix md_file objc_boehm_gc out_file out_object_file thread_file tm_file_list tm_include_list tm_defines tm_p_file_list tm_p_include_list xm_file_list xm_include_list xm_defines c_target_objs cxx_target_objs target_cpu_default GMPLIBS GMPINC LIBOBJS LTLIBOBJS'
+ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS build build_cpu build_vendor build_os host host_cpu host_vendor host_os target target_cpu target_vendor target_os target_noncanonical build_libsubdir build_subdir host_subdir target_subdir GENINSRC CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT NO_MINUS_C_MINUS_O OUTPUT_OPTION CPP EGREP loose_warn cxx_compat_warn strict_warn warn_cflags nocommon_flag TREEBROWSER valgrind_path valgrind_path_defines valgrind_command coverage_flags enable_multilib enable_decimal_float enable_shared TARGET_SYSTEM_ROOT TARGET_SYSTEM_ROOT_DEFINE CROSS_SYSTEM_HEADER_DIR onestep datarootdir docdir htmldir SET_MAKE AWK LN_S LN RANLIB ac_ct_RANLIB ranlib_flags INSTALL INSTALL_PROGRAM INSTALL_DATA make_compare_target have_mktemp_command MAKEINFO BUILD_INFO GENERATED_MANPAGES FLEX BISON NM AR COLLECT2_LIBS GNAT_LIBEXC LDEXP_LIB TARGET_GETGROUPS_T LIBICONV LTLIBICONV LIBICONV_DEP manext objext gthread_flags extra_modes_file extra_opt_files USE_NLS LIBINTL LIBINTL_DEP INCINTL XGETTEXT GMSGFMT POSUB CATALOGS DATADIRNAME INSTOBJEXT GENCAT CATOBJEXT host_cc_for_libada CROSS ALL SYSTEM_HEADER_DIR inhibit_libc CC_FOR_BUILD BUILD_CFLAGS STMP_FIXINC STMP_FIXPROTO collect2 gcc_cv_as ORIGINAL_AS_FOR_TARGET gcc_cv_ld ORIGINAL_LD_FOR_TARGET gcc_cv_nm ORIGINAL_NM_FOR_TARGET gcc_cv_objdump libgcc_visibility GGC zlibdir zlibinc MAINT gcc_tooldir dollar slibdir objdir subdirs srcdir all_compilers all_gtfiles all_lang_makefrags all_lang_makefiles all_languages all_selected_languages build_exeext build_install_headers_dir build_xm_file_list build_xm_include_list build_xm_defines check_languages cpp_install_dir xmake_file tmake_file extra_gcc_objs extra_headers_list extra_objs extra_parts extra_passes extra_programs float_h_file gcc_config_arguments gcc_gxx_include_dir host_exeext host_xm_file_list host_xm_include_list host_xm_defines out_host_hook_obj install lang_opt_files lang_specs_files lang_tree_files local_prefix md_file objc_boehm_gc out_file out_object_file thread_file tm_file_list tm_include_list tm_defines tm_p_file_list tm_p_include_list xm_file_list xm_include_list xm_defines c_target_objs cxx_target_objs target_cpu_default GMPLIBS GMPINC LIBOBJS LTLIBOBJS'
 ac_subst_files='language_hooks'
 
 # Initialize some variables set by options.
@@ -862,7 +862,7 @@ Optional Features:
                           put copies of generated files in source dir
                           intended for creating source tarballs for users
                           without texinfo bison or flex.
-  --enable-werror-always         enable -Werror always
+  --enable-werror-always  enable -Werror despite compiler version
   --enable-checking=LIST
 			  enable expensive run-time checks.  With LIST,
 			  enable only specific categories of checks.
@@ -6106,20 +6106,32 @@ fi
 # * overlong strings
 # So, we only use -pedantic if we can disable those warnings.
 
-echo "$as_me:$LINENO: checking whether ${CC} accepts -Wno-long-long" >&5
-echo $ECHO_N "checking whether ${CC} accepts -Wno-long-long... $ECHO_C" >&6
-if test "${ac_cv_prog_cc_w_no_long_long+set}" = set; then
+loose_warn=
+save_CFLAGS="$CFLAGS"
+for option in -W -Wall -Wwrite-strings -Wstrict-prototypes \
+			  -Wmissing-prototypes; do
+  as_acx_Woption=`echo "acx_cv_prog_cc_warning_$option" | $as_tr_sh`
+
+  echo "$as_me:$LINENO: checking whether $CC supports $option" >&5
+echo $ECHO_N "checking whether $CC supports $option... $ECHO_C" >&6
+if eval "test \"\${$as_acx_Woption+set}\" = set"; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
-  save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wno-long-long"
-  cat >conftest.$ac_ext <<_ACEOF
+  CFLAGS="$option"
+    cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 
+int
+main ()
+{
+
+  ;
+  return 0;
+}
 _ACEOF
 rm -f conftest.$ac_objext
 if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
@@ -6143,34 +6155,50 @@ if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ac_cv_prog_cc_w_no_long_long=yes
+  eval "$as_acx_Woption=yes"
 else
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-ac_cv_prog_cc_w_no_long_long=no
+eval "$as_acx_Woption=no"
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-  CFLAGS="$save_CFLAGS"
 
 fi
-echo "$as_me:$LINENO: result: $ac_cv_prog_cc_w_no_long_long" >&5
-echo "${ECHO_T}$ac_cv_prog_cc_w_no_long_long" >&6
+echo "$as_me:$LINENO: result: `eval echo '${'$as_acx_Woption'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_acx_Woption'}'`" >&6
+  if test `eval echo '${'$as_acx_Woption'}'` = yes; then
+  loose_warn="$loose_warn${loose_warn:+ }$option"
+fi
+
+  done
+CFLAGS="$save_CFLAGS"
+
+cxx_compat_warn=
+save_CFLAGS="$CFLAGS"
+for option in -Wc++-compat; do
+  as_acx_Woption=`echo "acx_cv_prog_cc_warning_$option" | $as_tr_sh`
 
-echo "$as_me:$LINENO: checking whether ${CC} accepts -Wno-variadic-macros" >&5
-echo $ECHO_N "checking whether ${CC} accepts -Wno-variadic-macros... $ECHO_C" >&6
-if test "${ac_cv_prog_cc_w_no_variadic_macros+set}" = set; then
+  echo "$as_me:$LINENO: checking whether $CC supports $option" >&5
+echo $ECHO_N "checking whether $CC supports $option... $ECHO_C" >&6
+if eval "test \"\${$as_acx_Woption+set}\" = set"; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
-  save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wno-variadic-macros"
-  cat >conftest.$ac_ext <<_ACEOF
+  CFLAGS="$option"
+    cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 
+int
+main ()
+{
+
+  ;
+  return 0;
+}
 _ACEOF
 rm -f conftest.$ac_objext
 if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
@@ -6194,34 +6222,51 @@ if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ac_cv_prog_cc_w_no_variadic_macros=yes
+  eval "$as_acx_Woption=yes"
 else
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-ac_cv_prog_cc_w_no_variadic_macros=no
+eval "$as_acx_Woption=no"
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-  CFLAGS="$save_CFLAGS"
 
 fi
-echo "$as_me:$LINENO: result: $ac_cv_prog_cc_w_no_variadic_macros" >&5
-echo "${ECHO_T}$ac_cv_prog_cc_w_no_variadic_macros" >&6
+echo "$as_me:$LINENO: result: `eval echo '${'$as_acx_Woption'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_acx_Woption'}'`" >&6
+  if test `eval echo '${'$as_acx_Woption'}'` = yes; then
+  cxx_compat_warn="$cxx_compat_warn${cxx_compat_warn:+ }$option"
+fi
+
+  done
+CFLAGS="$save_CFLAGS"
 
-echo "$as_me:$LINENO: checking whether ${CC} accepts -Wno-overlength-strings" >&5
-echo $ECHO_N "checking whether ${CC} accepts -Wno-overlength-strings... $ECHO_C" >&6
-if test "${ac_cv_prog_cc_w_no_overlength_strings+set}" = set; then
+strict_warn=
+save_CFLAGS="$CFLAGS"
+for option in -Wold-style-definition \
+                          -Wmissing-format-attribute; do
+  as_acx_Woption=`echo "acx_cv_prog_cc_warning_$option" | $as_tr_sh`
+
+  echo "$as_me:$LINENO: checking whether $CC supports $option" >&5
+echo $ECHO_N "checking whether $CC supports $option... $ECHO_C" >&6
+if eval "test \"\${$as_acx_Woption+set}\" = set"; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
-  save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wno-overlength-strings"
-  cat >conftest.$ac_ext <<_ACEOF
+  CFLAGS="$option"
+    cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 
+int
+main ()
+{
+
+  ;
+  return 0;
+}
 _ACEOF
 rm -f conftest.$ac_objext
 if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
@@ -6245,42 +6290,50 @@ if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ac_cv_prog_cc_w_no_overlength_strings=yes
+  eval "$as_acx_Woption=yes"
 else
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-ac_cv_prog_cc_w_no_overlength_strings=no
+eval "$as_acx_Woption=no"
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-  CFLAGS="$save_CFLAGS"
 
 fi
-echo "$as_me:$LINENO: result: $ac_cv_prog_cc_w_no_overlength_strings" >&5
-echo "${ECHO_T}$ac_cv_prog_cc_w_no_overlength_strings" >&6
-
-strict_warn=
-if test $ac_cv_prog_cc_w_no_long_long = yes \
-   && test $ac_cv_prog_cc_w_no_variadic_macros = yes \
-   && test $ac_cv_prog_cc_w_no_overlength_strings = yes ; then
-  strict_warn="-pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings"
+echo "$as_me:$LINENO: result: `eval echo '${'$as_acx_Woption'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_acx_Woption'}'`" >&6
+  if test `eval echo '${'$as_acx_Woption'}'` = yes; then
+  strict_warn="$strict_warn${strict_warn:+ }$option"
 fi
 
-# Add -Wold-style-definition if it's accepted
-echo "$as_me:$LINENO: checking whether ${CC} accepts -Wold-style-definition" >&5
-echo $ECHO_N "checking whether ${CC} accepts -Wold-style-definition... $ECHO_C" >&6
-if test "${ac_cv_prog_cc_w_old_style_definition+set}" = set; then
+  done
+CFLAGS="$save_CFLAGS"
+
+if test "$GCC" = yes; then
+  echo "$as_me:$LINENO: checking whether $CC supports -pedantic -Wno-long-long -Wno-variadic-macros \
+				     -Wno-overlength-strings" >&5
+echo $ECHO_N "checking whether $CC supports -pedantic -Wno-long-long -Wno-variadic-macros \
+				     -Wno-overlength-strings... $ECHO_C" >&6
+if test "${acx_cv_prog_cc_pedantic__Wno_long_long__Wno_variadic_macros_____________Wno_overlength_strings+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
   save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wold-style-definition"
-  cat >conftest.$ac_ext <<_ACEOF
+CFLAGS="-pedantic -Wno-long-long -Wno-variadic-macros \
+				     -Wno-overlength-strings"
+cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 
+int
+main ()
+{
+
+  ;
+  return 0;
+}
 _ACEOF
 rm -f conftest.$ac_objext
 if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
@@ -6304,151 +6357,44 @@ if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ac_cv_prog_cc_w_old_style_definition=yes
+  acx_cv_prog_cc_pedantic__Wno_long_long__Wno_variadic_macros_____________Wno_overlength_strings=yes
 else
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-ac_cv_prog_cc_w_old_style_definition=no
+acx_cv_prog_cc_pedantic__Wno_long_long__Wno_variadic_macros_____________Wno_overlength_strings=no
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-  CFLAGS="$save_CFLAGS"
-
+CFLAGS="$save_CFLAGS"
 fi
-echo "$as_me:$LINENO: result: $ac_cv_prog_cc_w_old_style_definition" >&5
-echo "${ECHO_T}$ac_cv_prog_cc_w_old_style_definition" >&6
-if test $ac_cv_prog_cc_w_old_style_definition = yes ; then
-  strict_warn="${strict_warn} -Wold-style-definition"
+echo "$as_me:$LINENO: result: $acx_cv_prog_cc_pedantic__Wno_long_long__Wno_variadic_macros_____________Wno_overlength_strings" >&5
+echo "${ECHO_T}$acx_cv_prog_cc_pedantic__Wno_long_long__Wno_variadic_macros_____________Wno_overlength_strings" >&6
+if test $acx_cv_prog_cc_pedantic__Wno_long_long__Wno_variadic_macros_____________Wno_overlength_strings = yes; then
+  strict_warn="$strict_warn${strict_warn:+ }-pedantic -Wno-long-long -Wno-variadic-macros \
+				     -Wno-overlength-strings"
 fi
 
-# Add -Wmissing-format-attribute if it's accepted
-echo "$as_me:$LINENO: checking whether ${CC} accepts -Wmissing-format-attribute" >&5
-echo $ECHO_N "checking whether ${CC} accepts -Wmissing-format-attribute... $ECHO_C" >&6
-if test "${ac_cv_prog_cc_w_missing_format_attribute+set}" = set; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wmissing-format-attribute"
-  cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
 
-_ACEOF
-rm -f conftest.$ac_objext
-if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
-  (eval $ac_compile) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } &&
-	 { ac_try='test -z "$ac_c_werror_flag"
-			 || test ! -s conftest.err'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; } &&
-	 { ac_try='test -s conftest.$ac_objext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  ac_cv_prog_cc_w_missing_format_attribute=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-ac_cv_prog_cc_w_missing_format_attribute=no
 fi
-rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-  CFLAGS="$save_CFLAGS"
 
-fi
-echo "$as_me:$LINENO: result: $ac_cv_prog_cc_w_missing_format_attribute" >&5
-echo "${ECHO_T}$ac_cv_prog_cc_w_missing_format_attribute" >&6
-if test $ac_cv_prog_cc_w_missing_format_attribute = yes ; then
-  strict_warn="${strict_warn} -Wmissing-format-attribute"
-fi
 
-# Enable -Werror, period.
-# Check whether --enable-werror_always or --disable-werror_always was given.
+# Check whether --enable-werror-always or --disable-werror-always was given.
 if test "${enable_werror_always+set}" = set; then
   enableval="$enable_werror_always"
 
 else
   enable_werror_always=no
 fi;
-if test x${enable_werror_always} = xyes ; then
-  strict_warn="${strict_warn} -Werror"
-fi
-
-
-# Get C++ compatibility warning flag, if supported.
-echo "$as_me:$LINENO: checking whether ${CC} accepts -Wc++-compat" >&5
-echo $ECHO_N "checking whether ${CC} accepts -Wc++-compat... $ECHO_C" >&6
-if test "${ac_cv_prog_cc_w_cxx_compat+set}" = set; then
-  echo $ECHO_N "(cached) $ECHO_C" >&6
-else
-  save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wc++-compat"
-  cat >conftest.$ac_ext <<_ACEOF
-/* confdefs.h.  */
-_ACEOF
-cat confdefs.h >>conftest.$ac_ext
-cat >>conftest.$ac_ext <<_ACEOF
-/* end confdefs.h.  */
-
-_ACEOF
-rm -f conftest.$ac_objext
-if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
-  (eval $ac_compile) 2>conftest.er1
-  ac_status=$?
-  grep -v '^ *+' conftest.er1 >conftest.err
-  rm -f conftest.er1
-  cat conftest.err >&5
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } &&
-	 { ac_try='test -z "$ac_c_werror_flag"
-			 || test ! -s conftest.err'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; } &&
-	 { ac_try='test -s conftest.$ac_objext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  ac_cv_prog_cc_w_cxx_compat=yes
-else
-  echo "$as_me: failed program was:" >&5
-sed 's/^/| /' conftest.$ac_ext >&5
-
-ac_cv_prog_cc_w_cxx_compat=no
+if test $enable_werror_always = yes; then
+  strict_warn="$strict_warn${strict_warn:+ }-Werror"
 fi
-rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-  CFLAGS="$save_CFLAGS"
 
-fi
-echo "$as_me:$LINENO: result: $ac_cv_prog_cc_w_cxx_compat" >&5
-echo "${ECHO_T}$ac_cv_prog_cc_w_cxx_compat" >&6
-if test x${ac_cv_prog_cc_w_cxx_compat} = xyes; then
-  cxx_compat_warn="-Wc++-compat"
-fi
 
 
 
-# If the native compiler is GCC, we can enable warnings even in stage1.
-# That's useful for people building cross-compilers, or just running a
-# quick `make'.
+# The above macros do nothing if the compiler is not GCC.  However, the
+# Makefile has more goo to add other flags, so this variabl is used to
+# enables warnings only for GCC.
 warn_cflags=
 if test "x$GCC" = "xyes"; then
   warn_cflags='$(GCC_WARN_CFLAGS)'
@@ -6527,6 +6473,7 @@ _ACEOF
 
   nocommon_flag=-fno-common
 fi
+
 if test x$ac_df_checking != x ; then
 
 cat >>confdefs.h <<\_ACEOF
@@ -6534,7 +6481,6 @@ cat >>confdefs.h <<\_ACEOF
 _ACEOF
 
 fi
-
 if test x$ac_assert_checking != x ; then
 
 cat >>confdefs.h <<\_ACEOF
@@ -7622,14 +7568,10 @@ echo "${ECHO_T}no" >&6
 fi
 
 
-MISSING="${CONFIG_SHELL-/bin/sh} $srcdir/../missing"
-
 # See if makeinfo has been installed and is modern enough
 # that we can use it.
 
-ac_executable_extensions="$build_exeext"
-
-# Extract the first word of "makeinfo", so it can be a program name with args.
+  # Extract the first word of "makeinfo", so it can be a program name with args.
 set dummy makeinfo; ac_word=$2
 echo "$as_me:$LINENO: checking for $ac_word" >&5
 echo $ECHO_N "checking for $ac_word... $ECHO_C" >&6
@@ -7664,32 +7606,33 @@ else
 echo "${ECHO_T}no" >&6
 fi
 
-if test -n "$MAKEINFO"; then
-  # Found it, now check the version.
-  echo "$as_me:$LINENO: checking for modern makeinfo" >&5
+  if test -n "$MAKEINFO"; then
+    # Found it, now check the version.
+    echo "$as_me:$LINENO: checking for modern makeinfo" >&5
 echo $ECHO_N "checking for modern makeinfo... $ECHO_C" >&6
 if test "${gcc_cv_prog_makeinfo_modern+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
-    ac_prog_version=`$MAKEINFO --version 2>&1 |
-                   sed -n 's/^.*GNU texinfo.* \([0-9][0-9.]*\).*$/\1/p'`
-  echo "configure:7676: version of makeinfo is $ac_prog_version" >&5
-  case $ac_prog_version in
-    '')     gcc_cv_prog_makeinfo_modern=no;;
-    4.[4-9]*)
-            gcc_cv_prog_makeinfo_modern=yes;;
-    *)      gcc_cv_prog_makeinfo_modern=no;;
-  esac
+  ac_prog_version=`eval $MAKEINFO --version 2>&1 |
+                                     sed -n 's/^.*GNU texinfo.* \([0-9][0-9.]*\).*$/\1/p'`
+
+                    case $ac_prog_version in
+                      '')  gcc_cv_prog_makeinfo_modern=no;;
+                      4.[4-9]*)  gcc_cv_prog_makeinfo_modern=yes;;
+                      *)   gcc_cv_prog_makeinfo_modern=no;;
+                    esac
 
 fi
 echo "$as_me:$LINENO: result: $gcc_cv_prog_makeinfo_modern" >&5
 echo "${ECHO_T}$gcc_cv_prog_makeinfo_modern" >&6
-else
-  gcc_cv_prog_makeinfo_modern=no
-fi
+  else
+    gcc_cv_prog_makeinfo_modern=no
+  fi
+  if test $gcc_cv_prog_makeinfo_modern = no; then
+    MAKEINFO="${CONFIG_SHELL-/bin/sh} $ac_aux_dir/missing makeinfo"
+  fi
 
 if test $gcc_cv_prog_makeinfo_modern = no; then
-  MAKEINFO="$MISSING makeinfo"
   { echo "$as_me:$LINENO: WARNING:
 *** Makeinfo is missing or too old.
 *** Info documentation will not be built." >&5
@@ -7716,6 +7659,8 @@ echo "${ECHO_T}no" >&6
 fi
 
 
+MISSING="${CONFIG_SHELL-/bin/sh} $ac_aux_dir/missing"
+
 # How about lex?
 for ac_prog in flex
 do
@@ -17671,8 +17616,9 @@ s,@NO_MINUS_C_MINUS_O@,$NO_MINUS_C_MINUS_O,;t t
 s,@OUTPUT_OPTION@,$OUTPUT_OPTION,;t t
 s,@CPP@,$CPP,;t t
 s,@EGREP@,$EGREP,;t t
-s,@strict_warn@,$strict_warn,;t t
+s,@loose_warn@,$loose_warn,;t t
 s,@cxx_compat_warn@,$cxx_compat_warn,;t t
+s,@strict_warn@,$strict_warn,;t t
 s,@warn_cflags@,$warn_cflags,;t t
 s,@nocommon_flag@,$nocommon_flag,;t t
 s,@TREEBROWSER@,$TREEBROWSER,;t t
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 0f13e99fd40..a6cde5bc47a 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -319,105 +319,18 @@ AC_CHECK_TYPES([__int64], [AC_CHECK_SIZEOF(__int64)])
 # * overlong strings
 # So, we only use -pedantic if we can disable those warnings.
 
-AC_CACHE_CHECK(
-  [whether ${CC} accepts -Wno-long-long],
-  [ac_cv_prog_cc_w_no_long_long],
-  [save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wno-long-long"
-  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])],
-                    [ac_cv_prog_cc_w_no_long_long=yes],
-                    [ac_cv_prog_cc_w_no_long_long=no])
-  CFLAGS="$save_CFLAGS"
-  ])
-
-AC_CACHE_CHECK(
-  [whether ${CC} accepts -Wno-variadic-macros],
-  [ac_cv_prog_cc_w_no_variadic_macros],
-  [save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wno-variadic-macros"
-  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])],
-                    [ac_cv_prog_cc_w_no_variadic_macros=yes],
-                    [ac_cv_prog_cc_w_no_variadic_macros=no])
-  CFLAGS="$save_CFLAGS"
-  ])
-
-AC_CACHE_CHECK(
-  [whether ${CC} accepts -Wno-overlength-strings],
-  [ac_cv_prog_cc_w_no_overlength_strings],
-  [save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wno-overlength-strings"
-  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])],
-                    [ac_cv_prog_cc_w_no_overlength_strings=yes],
-                    [ac_cv_prog_cc_w_no_overlength_strings=no])
-  CFLAGS="$save_CFLAGS"
-  ])
-
-strict_warn=
-if test $ac_cv_prog_cc_w_no_long_long = yes \
-   && test $ac_cv_prog_cc_w_no_variadic_macros = yes \
-   && test $ac_cv_prog_cc_w_no_overlength_strings = yes ; then
-  strict_warn="-pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings"
-fi
-
-# Add -Wold-style-definition if it's accepted
-AC_CACHE_CHECK(
-  [whether ${CC} accepts -Wold-style-definition],
-  [ac_cv_prog_cc_w_old_style_definition],
-  [save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wold-style-definition"
-  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])],
-                    [ac_cv_prog_cc_w_old_style_definition=yes],
-                    [ac_cv_prog_cc_w_old_style_definition=no])
-  CFLAGS="$save_CFLAGS"
-  ])
-if test $ac_cv_prog_cc_w_old_style_definition = yes ; then
-  strict_warn="${strict_warn} -Wold-style-definition"
-fi
-
-# Add -Wmissing-format-attribute if it's accepted
-AC_CACHE_CHECK(
-  [whether ${CC} accepts -Wmissing-format-attribute],
-  [ac_cv_prog_cc_w_missing_format_attribute],
-  [save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wmissing-format-attribute"
-  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])],
-                    [ac_cv_prog_cc_w_missing_format_attribute=yes],
-                    [ac_cv_prog_cc_w_missing_format_attribute=no])
-  CFLAGS="$save_CFLAGS"
-  ])
-if test $ac_cv_prog_cc_w_missing_format_attribute = yes ; then
-  strict_warn="${strict_warn} -Wmissing-format-attribute"
-fi
-
-# Enable -Werror, period.
-AC_ARG_ENABLE(werror_always, 
-[  --enable-werror-always         enable -Werror always], [],
-[enable_werror_always=no])
-if test x${enable_werror_always} = xyes ; then
-  strict_warn="${strict_warn} -Werror"
-fi
-AC_SUBST(strict_warn)
-
-# Get C++ compatibility warning flag, if supported.
-AC_CACHE_CHECK(
-  [whether ${CC} accepts -Wc++-compat],
-  [ac_cv_prog_cc_w_cxx_compat],
-  [save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wc++-compat"
-  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])],
-                    [ac_cv_prog_cc_w_cxx_compat=yes],
-                    [ac_cv_prog_cc_w_cxx_compat=no])
-  CFLAGS="$save_CFLAGS"
-  ])
-if test x${ac_cv_prog_cc_w_cxx_compat} = xyes; then
-  cxx_compat_warn="-Wc++-compat"
-fi
-AC_SUBST(cxx_compat_warn)
-
-
-# If the native compiler is GCC, we can enable warnings even in stage1.  
-# That's useful for people building cross-compilers, or just running a
-# quick `make'.
+ACX_PROG_CC_WARNING_OPTS([-W -Wall -Wwrite-strings -Wstrict-prototypes \
+			  -Wmissing-prototypes], [loose_warn])
+ACX_PROG_CC_WARNING_OPTS([-Wc++-compat], [cxx_compat_warn])
+ACX_PROG_CC_WARNING_OPTS([-Wold-style-definition \
+                          -Wmissing-format-attribute], [strict_warn])
+ACX_PROG_CC_WARNING_ALMOST_PEDANTIC([-Wno-long-long -Wno-variadic-macros \
+				     -Wno-overlength-strings], [strict_warn])
+ACX_PROG_CC_WARNINGS_ARE_ERRORS([manual], [strict_warn])
+
+# The above macros do nothing if the compiler is not GCC.  However, the
+# Makefile has more goo to add other flags, so this variabl is used to
+# enables warnings only for GCC.
 warn_cflags=
 if test "x$GCC" = "xyes"; then
   warn_cflags='$(GCC_WARN_CFLAGS)'
@@ -888,15 +801,12 @@ gcc_AC_PROG_CMP_IGNORE_INITIAL
 # See if we have the mktemp command.
 AC_CHECK_PROG(have_mktemp_command, mktemp, yes, no)
 
-MISSING="${CONFIG_SHELL-/bin/sh} $srcdir/../missing"
-
 # See if makeinfo has been installed and is modern enough
 # that we can use it.
-gcc_AC_CHECK_PROG_VER(MAKEINFO, makeinfo, --version,
+ACX_CHECK_PROG_VER(MAKEINFO, makeinfo, --version,
   [GNU texinfo.* \([0-9][0-9.]*\)],
   [4.[4-9]*])
 if test $gcc_cv_prog_makeinfo_modern = no; then
-  MAKEINFO="$MISSING makeinfo"
   AC_MSG_WARN([
 *** Makeinfo is missing or too old.
 *** Info documentation will not be built.])
@@ -917,6 +827,8 @@ else
 fi
 AC_SUBST(GENERATED_MANPAGES)
 
+MISSING="${CONFIG_SHELL-/bin/sh} $ac_aux_dir/missing"
+
 # How about lex?
 dnl Don't use AC_PROG_LEX; we insist on flex.
 dnl LEXLIB is not useful in gcc.
diff --git a/libiberty/ChangeLog b/libiberty/ChangeLog
index 233b175d5c7..9a80ed4a1f2 100644
--- a/libiberty/ChangeLog
+++ b/libiberty/ChangeLog
@@ -1,3 +1,9 @@
+2007-06-14  Paolo Bonzini  <bonzini@gnu.org>
+
+	* aclocal.m4: Include config/warnings.m4.
+	* configure.ac: Use ACX_PROG_CC_WARNING_OPTS.
+	* configure: Regenerate.
+
 2007-06-07  Geoffrey Keating  <geoffk@apple.com>
 
 	* configure.ac: Non-default multilibs can be cross compilations.
diff --git a/libiberty/aclocal.m4 b/libiberty/aclocal.m4
index 0b49d032122..643939e9d78 100644
--- a/libiberty/aclocal.m4
+++ b/libiberty/aclocal.m4
@@ -1,5 +1,6 @@
 sinclude(../config/acx.m4)
 sinclude(../config/no-executables.m4)
+sinclude(../config/warnings.m4)
 
 dnl See whether strncmp reads past the end of its string parameters.
 dnl On some versions of SunOS4 at least, strncmp reads a word at a time
diff --git a/libiberty/configure b/libiberty/configure
index c745d8ba34e..d350af78985 100755
--- a/libiberty/configure
+++ b/libiberty/configure
@@ -2953,22 +2953,33 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 ac_c_preproc_warn_flag=yes
 
-# Warn C++ incompatibilities if supported.
 
-echo "$as_me:$LINENO: checking whether ${CC} accepts -Wc++-compat" >&5
-echo $ECHO_N "checking whether ${CC} accepts -Wc++-compat... $ECHO_C" >&6
-if test "${ac_cv_prog_cc_w_cxx_compat+set}" = set; then
+ac_libiberty_warn_cflags=
+save_CFLAGS="$CFLAGS"
+for option in -W -Wall -pedantic -Wwrite-strings -Wc++-compat \
+			  -Wstrict-prototypes; do
+  as_acx_Woption=`echo "acx_cv_prog_cc_warning_$option" | $as_tr_sh`
+
+  echo "$as_me:$LINENO: checking whether $CC supports $option" >&5
+echo $ECHO_N "checking whether $CC supports $option... $ECHO_C" >&6
+if eval "test \"\${$as_acx_Woption+set}\" = set"; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
-  save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wc++-compat"
-  cat >conftest.$ac_ext <<_ACEOF
+  CFLAGS="$option"
+    cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
 
+int
+main ()
+{
+
+  ;
+  return 0;
+}
 _ACEOF
 rm -f conftest.$ac_objext
 if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
@@ -2992,28 +3003,25 @@ if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  ac_cv_prog_cc_w_cxx_compat=yes
+  eval "$as_acx_Woption=yes"
 else
   echo "$as_me: failed program was:" >&5
 sed 's/^/| /' conftest.$ac_ext >&5
 
-ac_cv_prog_cc_w_cxx_compat=no
+eval "$as_acx_Woption=no"
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
-  CFLAGS="$save_CFLAGS"
 
 fi
-echo "$as_me:$LINENO: result: $ac_cv_prog_cc_w_cxx_compat" >&5
-echo "${ECHO_T}$ac_cv_prog_cc_w_cxx_compat" >&6
-
-
-if test x$GCC = xyes; then
-  ac_libiberty_warn_cflags='-W -Wall -pedantic -Wwrite-strings -Wstrict-prototypes'
-fi
-if test $ac_cv_prog_cc_w_cxx_compat = yes ; then
-  ac_libiberty_warn_cflags="${ac_libiberty_warn_cflags} -Wc++-compat"
+echo "$as_me:$LINENO: result: `eval echo '${'$as_acx_Woption'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_acx_Woption'}'`" >&6
+  if test `eval echo '${'$as_acx_Woption'}'` = yes; then
+  ac_libiberty_warn_cflags="$ac_libiberty_warn_cflags${ac_libiberty_warn_cflags:+ }$option"
 fi
 
+  done
+CFLAGS="$save_CFLAGS"
+
 
 if test "x$CC" != xcc; then
   echo "$as_me:$LINENO: checking whether $CC and cc understand -c and -o together" >&5
diff --git a/libiberty/configure.ac b/libiberty/configure.ac
index cdc3cd38f62..82123781b39 100644
--- a/libiberty/configure.ac
+++ b/libiberty/configure.ac
@@ -132,26 +132,8 @@ GCC_NO_EXECUTABLES
 AC_PROG_CC
 AC_PROG_CPP_WERROR
 
-# Warn C++ incompatibilities if supported.
-AC_CACHE_CHECK(
-  [whether ${CC} accepts -Wc++-compat],
-  [ac_cv_prog_cc_w_cxx_compat],
-  [save_CFLAGS="$CFLAGS"
-  CFLAGS="-Wc++-compat"
-  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[]])],
-                    [ac_cv_prog_cc_w_cxx_compat=yes],
-                    [ac_cv_prog_cc_w_cxx_compat=no])
-  CFLAGS="$save_CFLAGS"
-  ])
-
-
-if test x$GCC = xyes; then
-  ac_libiberty_warn_cflags='-W -Wall -pedantic -Wwrite-strings -Wstrict-prototypes'
-fi
-if test $ac_cv_prog_cc_w_cxx_compat = yes ; then
-  ac_libiberty_warn_cflags="${ac_libiberty_warn_cflags} -Wc++-compat"
-fi
-AC_SUBST(ac_libiberty_warn_cflags)
+ACX_PROG_CC_WARNING_OPTS([-W -Wall -pedantic -Wwrite-strings -Wc++-compat \
+			  -Wstrict-prototypes], [ac_libiberty_warn_cflags])
 
 AC_PROG_CC_C_O
 # autoconf is lame and doesn't give us any substitution variable for this.