PR libstdc++/86450 use -Wabi=2 and simplify -Werror use

Use -Wabi=2 to fix warnings about -Wabi having no effect on its own.
This requires suppressing two warnings in src/c++11/debug.cc which do
not affect the library ABI.

Previously libstdc++ defaulted to --enable-werror but the -Werror flag
was not actually added unless --enable-maintainer-mode was used. This is
not documented and not the expected behaviour. This removes any special
treatment for maintainer-mode, makes -Werror depend directly on
--enable-werror, and changes the default to --enable-werror=no.

	PR libstdc++/86450
	* acinclude.m4 (GLIBCXX_CHECK_COMPILER_FEATURES): Don't define WERROR.
	(GLIBCXX_EXPORT_FLAGS): Use -Wabi=2 instead of -Wabi.
	* configure: Regenerate.
	* configure.ac: Change GLIBCXX_ENABLE_WERROR default to "no".
	* doc/Makefile.in: Regenerate.
	* fragment.am: Set WERROR_FLAG to -Werror instead of $(WERROR).
	* include/Makefile.in: Regenerate.
	* libsupc++/Makefile.in: Regenerate.
	* po/Makefile.in: Regenerate.
	* python/Makefile.in: Regenerate.
	* src/Makefile.in: Regenerate.
	* src/c++11/Makefile.in: Regenerate.
	* src/c++11/debug.cc: Use diagnostic pragmas to suppress warnings
	from -Wabi=2 that don't affect exported symbols.
	* src/c++98/Makefile.in: Regenerate.
	* src/filesystem/Makefile.in: Regenerate.
	* testsuite/Makefile.in: Regenerate.

From-SVN: r262824

17 files changed, 55 insertions, 91 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 33b2eea8247..4345d299ded 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,24 @@
 2018-07-17  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/86450
+	* acinclude.m4 (GLIBCXX_CHECK_COMPILER_FEATURES): Don't define WERROR.
+	(GLIBCXX_EXPORT_FLAGS): Use -Wabi=2 instead of -Wabi.
+	* configure: Regenerate.
+	* configure.ac: Change GLIBCXX_ENABLE_WERROR default to "no".
+	* doc/Makefile.in: Regenerate.
+	* fragment.am: Set WERROR_FLAG to -Werror instead of $(WERROR).
+	* include/Makefile.in: Regenerate.
+	* libsupc++/Makefile.in: Regenerate.
+	* po/Makefile.in: Regenerate.
+	* python/Makefile.in: Regenerate.
+	* src/Makefile.in: Regenerate.
+	* src/c++11/Makefile.in: Regenerate.
+	* src/c++11/debug.cc: Use diagnostic pragmas to suppress warnings
+	from -Wabi=2 that don't affect exported symbols.
+	* src/c++98/Makefile.in: Regenerate.
+	* src/filesystem/Makefile.in: Regenerate.
+	* testsuite/Makefile.in: Regenerate.
+
 	* src/c++11/compatibility-thread-c++0x.cc [_GLIBCXX_SHARED]
 	(_Async_state_common::_M_join): Simplify use of std::call_once and
 	corresponding explicit instantiation.
diff --git a/libstdc++-v3/Makefile.in b/libstdc++-v3/Makefile.in
index dbfdce67638..f24f5d8803b 100644
--- a/libstdc++-v3/Makefile.in
+++ b/libstdc++-v3/Makefile.in
@@ -232,7 +232,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -328,7 +327,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index cf5add167e6..bbf3c8df3e1 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -140,13 +140,6 @@ AC_DEFUN([GLIBCXX_CHECK_COMPILER_FEATURES], [
   ac_test_CXXFLAGS="${CXXFLAGS+set}"
   ac_save_CXXFLAGS="$CXXFLAGS"
 
-  # Check for maintainer-mode bits.
-  if test x"$USE_MAINTAINER_MODE" = xno; then
-    WERROR=''
-  else
-    WERROR='-Werror'
-  fi
-
   # Check for -ffunction-sections -fdata-sections
   AC_MSG_CHECKING([for g++ that supports -ffunction-sections -fdata-sections])
   CXXFLAGS='-g -Werror -ffunction-sections -fdata-sections'
@@ -163,7 +156,6 @@ AC_DEFUN([GLIBCXX_CHECK_COMPILER_FEATURES], [
   AC_MSG_RESULT($ac_fdsections)
 
   AC_LANG_RESTORE
-  AC_SUBST(WERROR)
   AC_SUBST(SECTION_FLAGS)
 ])
 
@@ -733,7 +725,7 @@ AC_DEFUN([GLIBCXX_EXPORT_FLAGS], [
   # OPTIMIZE_CXXFLAGS = -O3 -fstrict-aliasing -fvtable-gc
   AC_SUBST(OPTIMIZE_CXXFLAGS)
 
-  WARN_FLAGS='-Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi'
+  WARN_FLAGS="-Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi=2"
   AC_SUBST(WARN_FLAGS)
 ])
 
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index d126addd40a..101dcd9cb7c 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -728,7 +728,6 @@ BASIC_FILE_CC
 BASIC_FILE_H
 CSTDIO_H
 SECTION_FLAGS
-WERROR
 ENABLE_FLOAT128_FALSE
 ENABLE_FLOAT128_TRUE
 thread_header
@@ -1582,7 +1581,7 @@ Optional Features:
                           memory [default=no]
   --enable-extern-template
                           enable extern template [default=yes]
-  --enable-werror         turns on -Werror [default=yes]
+  --enable-werror         turns on -Werror [default=no]
   --enable-vtable-verify  enable vtable verify [default=no]
   --enable-libstdcxx-time[=KIND]
                           use KIND for check type [default=auto]
@@ -11608,7 +11607,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11611 "configure"
+#line 11610 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11714,7 +11713,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11717 "configure"
+#line 11716 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -12885,20 +12884,20 @@ if test -z "$aix_libpath"; then aix_libpath="/usr/lib:/lib"; fi
 	      prelink_cmds_CXX='tpldir=Template.dir~
 		rm -rf $tpldir~
 		$CC --prelink_objects --instantiation_dir $tpldir $objs $libobjs $compile_deplibs~
-		compile_command="$compile_command `find $tpldir -name \*.o | $NL2SP`"'
+		compile_command="$compile_command `find $tpldir -name \*.o | sort | $NL2SP`"'
 	      old_archive_cmds_CXX='tpldir=Template.dir~
 		rm -rf $tpldir~
 		$CC --prelink_objects --instantiation_dir $tpldir $oldobjs$old_deplibs~
-		$AR $AR_FLAGS $oldlib$oldobjs$old_deplibs `find $tpldir -name \*.o | $NL2SP`~
+		$AR $AR_FLAGS $oldlib$oldobjs$old_deplibs `find $tpldir -name \*.o | sort | $NL2SP`~
 		$RANLIB $oldlib'
 	      archive_cmds_CXX='tpldir=Template.dir~
 		rm -rf $tpldir~
 		$CC --prelink_objects --instantiation_dir $tpldir $predep_objects $libobjs $deplibs $convenience $postdep_objects~
-		$CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | $NL2SP` $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname -o $lib'
+		$CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | sort | $NL2SP` $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname -o $lib'
 	      archive_expsym_cmds_CXX='tpldir=Template.dir~
 		rm -rf $tpldir~
 		$CC --prelink_objects --instantiation_dir $tpldir $predep_objects $libobjs $deplibs $convenience $postdep_objects~
-		$CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | $NL2SP` $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname ${wl}-retain-symbols-file ${wl}$export_symbols -o $lib'
+		$CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | sort | $NL2SP` $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname ${wl}-retain-symbols-file ${wl}$export_symbols -o $lib'
 	      ;;
 	    *) # Version 6 and above use weak symbols
 	      archive_cmds_CXX='$CC -shared $pic_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname -o $lib'
@@ -15400,7 +15399,7 @@ $as_echo "$glibcxx_cv_atomic_long_long" >&6; }
   # Fake what AC_TRY_COMPILE does.
 
     cat > conftest.$ac_ext << EOF
-#line 15403 "configure"
+#line 15402 "configure"
 int main()
 {
   typedef bool atomic_type;
@@ -15435,7 +15434,7 @@ $as_echo "$glibcxx_cv_atomic_bool" >&6; }
     rm -f conftest*
 
     cat > conftest.$ac_ext << EOF
-#line 15438 "configure"
+#line 15437 "configure"
 int main()
 {
   typedef short atomic_type;
@@ -15470,7 +15469,7 @@ $as_echo "$glibcxx_cv_atomic_short" >&6; }
     rm -f conftest*
 
     cat > conftest.$ac_ext << EOF
-#line 15473 "configure"
+#line 15472 "configure"
 int main()
 {
   // NB: _Atomic_word not necessarily int.
@@ -15506,7 +15505,7 @@ $as_echo "$glibcxx_cv_atomic_int" >&6; }
     rm -f conftest*
 
     cat > conftest.$ac_ext << EOF
-#line 15509 "configure"
+#line 15508 "configure"
 int main()
 {
   typedef long long atomic_type;
@@ -15587,7 +15586,7 @@ $as_echo "$as_me: WARNING: Performance of certain classes will degrade as a resu
   # unnecessary for this test.
 
     cat > conftest.$ac_ext << EOF
-#line 15590 "configure"
+#line 15589 "configure"
 int main()
 {
   _Decimal32 d1;
@@ -15629,7 +15628,7 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
   # unnecessary for this test.
 
     cat > conftest.$ac_ext << EOF
-#line 15632 "configure"
+#line 15631 "configure"
 template<typename T1, typename T2>
   struct same
   { typedef T2 type; };
@@ -15663,7 +15662,7 @@ $as_echo "$enable_int128" >&6; }
     rm -f conftest*
 
     cat > conftest.$ac_ext << EOF
-#line 15666 "configure"
+#line 15665 "configure"
 template<typename T1, typename T2>
   struct same
   { typedef T2 type; };
@@ -15720,13 +15719,6 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
   ac_test_CXXFLAGS="${CXXFLAGS+set}"
   ac_save_CXXFLAGS="$CXXFLAGS"
 
-  # Check for maintainer-mode bits.
-  if test x"$USE_MAINTAINER_MODE" = xno; then
-    WERROR=''
-  else
-    WERROR='-Werror'
-  fi
-
   # Check for -ffunction-sections -fdata-sections
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for g++ that supports -ffunction-sections -fdata-sections" >&5
 $as_echo_n "checking for g++ that supports -ffunction-sections -fdata-sections... " >&6; }
@@ -15769,7 +15761,6 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-
 # Enable all the variable C++ runtime options that don't require linking.
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for underlying I/O to use" >&5
@@ -18104,7 +18095,7 @@ if test "${enable_werror+set}" = set; then :
       esac
 
 else
-  enable_werror=yes
+  enable_werror=no
 fi
 
 
@@ -29055,13 +29046,6 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
   ac_test_CXXFLAGS="${CXXFLAGS+set}"
   ac_save_CXXFLAGS="$CXXFLAGS"
 
-  # Check for maintainer-mode bits.
-  if test x"$USE_MAINTAINER_MODE" = xno; then
-    WERROR=''
-  else
-    WERROR='-Werror'
-  fi
-
   # Check for -ffunction-sections -fdata-sections
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for g++ that supports -ffunction-sections -fdata-sections" >&5
 $as_echo_n "checking for g++ that supports -ffunction-sections -fdata-sections... " >&6; }
@@ -29104,7 +29088,6 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-
   # If we're not using GNU ld, then there's no point in even trying these
   # tests.  Check for that first.  We should have already tested for gld
   # by now (in libtool), but require it now just to be safe...
@@ -35049,13 +35032,6 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
   ac_test_CXXFLAGS="${CXXFLAGS+set}"
   ac_save_CXXFLAGS="$CXXFLAGS"
 
-  # Check for maintainer-mode bits.
-  if test x"$USE_MAINTAINER_MODE" = xno; then
-    WERROR=''
-  else
-    WERROR='-Werror'
-  fi
-
   # Check for -ffunction-sections -fdata-sections
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for g++ that supports -ffunction-sections -fdata-sections" >&5
 $as_echo_n "checking for g++ that supports -ffunction-sections -fdata-sections... " >&6; }
@@ -35098,7 +35074,6 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-
   # If we're not using GNU ld, then there's no point in even trying these
   # tests.  Check for that first.  We should have already tested for gld
   # by now (in libtool), but require it now just to be safe...
@@ -53809,13 +53784,6 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
   ac_test_CXXFLAGS="${CXXFLAGS+set}"
   ac_save_CXXFLAGS="$CXXFLAGS"
 
-  # Check for maintainer-mode bits.
-  if test x"$USE_MAINTAINER_MODE" = xno; then
-    WERROR=''
-  else
-    WERROR='-Werror'
-  fi
-
   # Check for -ffunction-sections -fdata-sections
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for g++ that supports -ffunction-sections -fdata-sections" >&5
 $as_echo_n "checking for g++ that supports -ffunction-sections -fdata-sections... " >&6; }
@@ -53858,7 +53826,6 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-
   # If we're not using GNU ld, then there's no point in even trying these
   # tests.  Check for that first.  We should have already tested for gld
   # by now (in libtool), but require it now just to be safe...
@@ -66510,13 +66477,6 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
   ac_test_CXXFLAGS="${CXXFLAGS+set}"
   ac_save_CXXFLAGS="$CXXFLAGS"
 
-  # Check for maintainer-mode bits.
-  if test x"$USE_MAINTAINER_MODE" = xno; then
-    WERROR=''
-  else
-    WERROR='-Werror'
-  fi
-
   # Check for -ffunction-sections -fdata-sections
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for g++ that supports -ffunction-sections -fdata-sections" >&5
 $as_echo_n "checking for g++ that supports -ffunction-sections -fdata-sections... " >&6; }
@@ -66559,7 +66519,6 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
-
   # If we're not using GNU ld, then there's no point in even trying these
   # tests.  Check for that first.  We should have already tested for gld
   # by now (in libtool), but require it now just to be safe...
@@ -81846,7 +81805,7 @@ $as_echo "$gxx_include_dir" >&6; }
   # OPTIMIZE_CXXFLAGS = -O3 -fstrict-aliasing -fvtable-gc
 
 
-  WARN_FLAGS='-Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi'
+  WARN_FLAGS="-Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi=2"
 
 
 
diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac
index 7e1fd84606a..1e0a33fb3ea 100644
--- a/libstdc++-v3/configure.ac
+++ b/libstdc++-v3/configure.ac
@@ -175,7 +175,7 @@ GLIBCXX_ENABLE_CXX_FLAGS
 GLIBCXX_ENABLE_FULLY_DYNAMIC_STRING([no])
 GLIBCXX_ENABLE_EXTERN_TEMPLATE([yes])
 GLIBCXX_ENABLE_PYTHON
-GLIBCXX_ENABLE_WERROR([yes])
+GLIBCXX_ENABLE_WERROR([no])
 GLIBCXX_ENABLE_VTABLE_VERIFY([no])
 
 # Checks for operating systems support that doesn't require linking.
diff --git a/libstdc++-v3/doc/Makefile.in b/libstdc++-v3/doc/Makefile.in
index f68b1d72d10..c19f7bdf340 100644
--- a/libstdc++-v3/doc/Makefile.in
+++ b/libstdc++-v3/doc/Makefile.in
@@ -204,7 +204,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 
 # Validate existing XML structure.
 XMLLINT = xmllint
@@ -310,7 +309,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/fragment.am b/libstdc++-v3/fragment.am
index 898569520b9..216c572fc60 100644
--- a/libstdc++-v3/fragment.am
+++ b/libstdc++-v3/fragment.am
@@ -14,9 +14,9 @@ toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 
 if ENABLE_WERROR
-WERROR_FLAG=$(WERROR)
+WERROR_FLAG = -Werror
 else
-WERROR_FLAG=
+WERROR_FLAG =
 endif
 
 if ENABLE_EXTERN_TEMPLATE
diff --git a/libstdc++-v3/include/Makefile.in b/libstdc++-v3/include/Makefile.in
index 1a4dbbf8716..ff3249e346e 100644
--- a/libstdc++-v3/include/Makefile.in
+++ b/libstdc++-v3/include/Makefile.in
@@ -204,7 +204,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -300,7 +299,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/libsupc++/Makefile.in b/libstdc++-v3/libsupc++/Makefile.in
index 37644e8f4cc..1e63bab6a09 100644
--- a/libstdc++-v3/libsupc++/Makefile.in
+++ b/libstdc++-v3/libsupc++/Makefile.in
@@ -277,7 +277,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -373,7 +372,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/po/Makefile.in b/libstdc++-v3/po/Makefile.in
index 3fe137f1d97..1f0ac5bf526 100644
--- a/libstdc++-v3/po/Makefile.in
+++ b/libstdc++-v3/po/Makefile.in
@@ -204,7 +204,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -300,7 +299,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/python/Makefile.in b/libstdc++-v3/python/Makefile.in
index 23fe7a6a697..f033a0589fa 100644
--- a/libstdc++-v3/python/Makefile.in
+++ b/libstdc++-v3/python/Makefile.in
@@ -234,7 +234,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -330,7 +329,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/src/Makefile.in b/libstdc++-v3/src/Makefile.in
index f0ec7bc8e8e..d427ed539da 100644
--- a/libstdc++-v3/src/Makefile.in
+++ b/libstdc++-v3/src/Makefile.in
@@ -267,7 +267,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -363,7 +362,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/src/c++11/Makefile.in b/libstdc++-v3/src/c++11/Makefile.in
index 977f1ab441d..d4c4b72a1ae 100644
--- a/libstdc++-v3/src/c++11/Makefile.in
+++ b/libstdc++-v3/src/c++11/Makefile.in
@@ -242,7 +242,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -338,7 +337,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/src/c++11/debug.cc b/libstdc++-v3/src/c++11/debug.cc
index cb64dd9240e..88fe889dd6a 100644
--- a/libstdc++-v3/src/c++11/debug.cc
+++ b/libstdc++-v3/src/c++11/debug.cc
@@ -66,6 +66,10 @@ namespace
     return __gnu_internal::get_mutex(index);
   }
 
+#pragma GCC diagnostic push
+// Suppress -Wabi=2 warnings due to PR c++/51322 mangling change
+#pragma GCC diagnostic warning "-Wabi=6"
+
   void
   swap_its(__gnu_debug::_Safe_sequence_base& __lhs,
 	   __gnu_debug::_Safe_iterator_base*& __lhs_its,
@@ -90,6 +94,7 @@ namespace
     swap_its(__lhs, __lhs._M_const_iterators,
 	     __rhs, __rhs._M_const_iterators);
   }
+#pragma GCC diagnostic pop
 
   template<typename _Action>
     void
diff --git a/libstdc++-v3/src/c++98/Makefile.in b/libstdc++-v3/src/c++98/Makefile.in
index d2b9079795c..33f2ac0f87a 100644
--- a/libstdc++-v3/src/c++98/Makefile.in
+++ b/libstdc++-v3/src/c++98/Makefile.in
@@ -238,7 +238,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -334,7 +333,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/src/filesystem/Makefile.in b/libstdc++-v3/src/filesystem/Makefile.in
index 0b43889eeb2..e38115afecc 100644
--- a/libstdc++-v3/src/filesystem/Makefile.in
+++ b/libstdc++-v3/src/filesystem/Makefile.in
@@ -248,7 +248,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -344,7 +343,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates
 
diff --git a/libstdc++-v3/testsuite/Makefile.in b/libstdc++-v3/testsuite/Makefile.in
index ddae2b2cd55..8f40961da83 100644
--- a/libstdc++-v3/testsuite/Makefile.in
+++ b/libstdc++-v3/testsuite/Makefile.in
@@ -204,7 +204,6 @@ VTV_CXXFLAGS = @VTV_CXXFLAGS@
 VTV_CXXLINKFLAGS = @VTV_CXXLINKFLAGS@
 VTV_PCH_CXXFLAGS = @VTV_PCH_CXXFLAGS@
 WARN_FLAGS = @WARN_FLAGS@
-WERROR = @WERROR@
 XMLLINT = @XMLLINT@
 XSLTPROC = @XSLTPROC@
 XSL_STYLE_DIR = @XSL_STYLE_DIR@
@@ -303,7 +302,7 @@ STAMP = echo timestamp >
 toolexecdir = $(glibcxx_toolexecdir)
 toolexeclibdir = $(glibcxx_toolexeclibdir)
 @ENABLE_WERROR_FALSE@WERROR_FLAG = 
-@ENABLE_WERROR_TRUE@WERROR_FLAG = $(WERROR)
+@ENABLE_WERROR_TRUE@WERROR_FLAG = -Werror
 @ENABLE_EXTERN_TEMPLATE_FALSE@XTEMPLATE_FLAGS = 
 @ENABLE_EXTERN_TEMPLATE_TRUE@XTEMPLATE_FLAGS = -fno-implicit-templates