config/warnings.m4 - rust-lang/gcc - Git at Google

 # Autoconf include file defining macros related to compile-time warnings.

 # Copyright 2004, 2005, 2007, 2009, 2011 Free Software Foundation, Inc.

 #This file is part of GCC.

 #GCC is free software; you can redistribute it and/or modify it under
 #the terms of the GNU General Public License as published by the Free
 #Software Foundation; either version 3, or (at your option) any later
 #version.

 #GCC is distributed in the hope that it will be useful, but WITHOUT
 #ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 #FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 #for more details.

 #You should have received a copy of the GNU General Public License
 #along with GCC; see the file COPYING3.  If not see
 #<http://www.gnu.org/licenses/>.

 # ACX_PROG_CC_WARNING_OPTS(WARNINGS, [VARIABLE = WARN_CFLAGS])
 #   Sets @VARIABLE@ to the subset of the given options which the
 #   compiler accepts.
 AC_DEFUN([ACX_PROG_CC_WARNING_OPTS],
 [AC_REQUIRE([AC_PROG_CC])dnl
 AC_LANG_PUSH(C)
 m4_pushdef([acx_Var], [m4_default([$2], [WARN_CFLAGS])])dnl
 AC_SUBST(acx_Var)dnl
 m4_expand_once([acx_Var=
 ],m4_quote(acx_Var=))dnl
 save_CFLAGS="$CFLAGS"
 for real_option in $1; do
   # Do the check with the no- prefix removed since gcc silently
   # accepts any -Wno-* option on purpose
   case $real_option in
     -Wno-*) option=-W`expr x$real_option : 'x-Wno-\(.*\)'` ;;
     *) option=$real_option ;;
   esac
   AS_VAR_PUSHDEF([acx_Woption], [acx_cv_prog_cc_warning_$option])
   AC_CACHE_CHECK([whether $CC supports $option], acx_Woption,
     [CFLAGS="$option"
     AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
       [AS_VAR_SET(acx_Woption, yes)],
       [AS_VAR_SET(acx_Woption, no)])
   ])
   AS_IF([test AS_VAR_GET(acx_Woption) = yes],
         [acx_Var="$acx_Var${acx_Var:+ }$real_option"])
   AS_VAR_POPDEF([acx_Woption])dnl
 done
 CFLAGS="$save_CFLAGS"
 m4_popdef([acx_Var])dnl
 AC_LANG_POP(C)
 ])# ACX_PROG_CC_WARNING_OPTS

 # ACX_PROG_CC_WARNING_ALMOST_PEDANTIC(WARNINGS, [VARIABLE = WARN_PEDANTIC])
 #   Append to VARIABLE "-pedantic" + the argument, if the compiler is GCC
 #   and accepts all of those options simultaneously, otherwise to nothing.
 AC_DEFUN([ACX_PROG_CC_WARNING_ALMOST_PEDANTIC],
 [AC_REQUIRE([AC_PROG_CC])dnl
 AC_LANG_PUSH(C)
 m4_pushdef([acx_Var], [m4_default([$2], [WARN_PEDANTIC])])dnl
 AC_SUBST(acx_Var)dnl
 m4_expand_once([acx_Var=
 ],m4_quote(acx_Var=))dnl
 # Do the check with the no- prefix removed from the warning options
 # since gcc silently accepts any -Wno-* option on purpose
 m4_pushdef([acx_Woptions], [m4_bpatsubst([$1], [-Wno-], [-W])])dnl
 AS_VAR_PUSHDEF([acx_Pedantic], [acx_cv_prog_cc_pedantic_]acx_Woptions)dnl
 AS_IF([test "$GCC" = yes],
 [AC_CACHE_CHECK([whether $CC supports -pedantic ]acx_Woptions, acx_Pedantic,
 [save_CFLAGS="$CFLAGS"
 CFLAGS="-pedantic acx_Woptions"
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
    [AS_VAR_SET(acx_Pedantic, yes)],
    [AS_VAR_SET(acx_Pedantic, no)])
 CFLAGS="$save_CFLAGS"])
 AS_IF([test AS_VAR_GET(acx_Pedantic) = yes],
       [acx_Var="$acx_Var${acx_Var:+ }-pedantic $1"])
 ])
 AS_VAR_POPDEF([acx_Pedantic])dnl
 m4_popdef([acx_Woptions])dnl
 m4_popdef([acx_Var])dnl
 AC_LANG_POP(C)
 ])# ACX_PROG_CC_WARNING_ALMOST_PEDANTIC

 # ACX_PROG_CC_WARNINGS_ARE_ERRORS([x.y.z], [VARIABLE = WERROR])
 #   sets @VARIABLE@ to "-Werror" if the compiler is GCC >=x.y.z, or if
 #   --enable-werror-always was given on the command line, otherwise
 #   to nothing.
 #   If the argument is the word "manual" instead of a version number,
 #   then @VARIABLE@ will be set to -Werror only if --enable-werror-always
 #   appeared on the configure command line.
 AC_DEFUN([ACX_PROG_CC_WARNINGS_ARE_ERRORS],
 [AC_REQUIRE([AC_PROG_CC])dnl
 AC_LANG_PUSH(C)
 m4_pushdef([acx_Var], [m4_default([$2], [WERROR])])dnl
 AC_SUBST(acx_Var)dnl
 m4_expand_once([acx_Var=
 ],m4_quote(acx_Var=))dnl
 AC_ARG_ENABLE(werror-always,
     AS_HELP_STRING([--enable-werror-always],
 		   [enable -Werror despite compiler version]),
 [], [enable_werror_always=no])
 AS_IF([test $enable_werror_always = yes],
       [acx_Var="$acx_Var${acx_Var:+ }-Werror"])
  m4_if($1, [manual],,
  [AS_VAR_PUSHDEF([acx_GCCvers], [acx_cv_prog_cc_gcc_$1_or_newer])dnl
   AC_CACHE_CHECK([whether $CC is GCC >=$1], acx_GCCvers,
     [set fnord `echo $1 | tr '.' ' '`
      shift
      AC_PREPROC_IFELSE(
 [#if __GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__ \
   < [$]1 * 10000 + [$]2 * 100 + [$]3
 #error insufficient
 #endif],
    [AS_VAR_SET(acx_GCCvers, yes)],
    [AS_VAR_SET(acx_GCCvers, no)])])
  AS_IF([test AS_VAR_GET(acx_GCCvers) = yes],
        [acx_Var="$acx_Var${acx_Var:+ }-Werror"])
   AS_VAR_POPDEF([acx_GCCvers])])
 m4_popdef([acx_Var])dnl
 AC_LANG_POP(C)
 ])# ACX_PROG_CC_WARNINGS_ARE_ERRORS

 # ACX_PROG_CXX_WARNING_OPTS(WARNINGS, [VARIABLE = WARN_CXXFLAGS])
 #   Sets @VARIABLE@ to the subset of the given options which the
 #   compiler accepts.
 AC_DEFUN([ACX_PROG_CXX_WARNING_OPTS],
 [AC_REQUIRE([AC_PROG_CXX])dnl
 AC_LANG_PUSH(C++)
 m4_pushdef([acx_Var], [m4_default([$2], [WARN_CXXFLAGS])])dnl
 AC_SUBST(acx_Var)dnl
 m4_expand_once([acx_Var=
 ],m4_quote(acx_Var=))dnl
 save_CXXFLAGS="$CXXFLAGS"
 for real_option in $1; do
   # Do the check with the no- prefix removed since gcc silently
   # accepts any -Wno-* option on purpose
   case $real_option in
     -Wno-*) option=-W`expr x$real_option : 'x-Wno-\(.*\)'` ;;
     *) option=$real_option ;;
   esac
   AS_VAR_PUSHDEF([acx_Woption], [acx_cv_prog_cc_warning_$option])
   AC_CACHE_CHECK([whether $CXX supports $option], acx_Woption,
     [CXXFLAGS="$option"
     AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
       [AS_VAR_SET(acx_Woption, yes)],
       [AS_VAR_SET(acx_Woption, no)])
   ])
   AS_IF([test AS_VAR_GET(acx_Woption) = yes],
         [acx_Var="$acx_Var${acx_Var:+ }$real_option"])
   AS_VAR_POPDEF([acx_Woption])dnl
 done
 CXXFLAGS="$save_CXXFLAGS"
 m4_popdef([acx_Var])dnl
 AC_LANG_POP(C++)
 ])# ACX_PROG_CXX_WARNING_OPTS

 # ACX_PROG_CXX_WARNING_ALMOST_PEDANTIC(WARNINGS, [VARIABLE = WARN_PEDANTIC])
 #   Append to VARIABLE "-pedantic" + the argument, if the compiler is G++
 #   and accepts all of those options simultaneously, otherwise to nothing.
 AC_DEFUN([ACX_PROG_CXX_WARNING_ALMOST_PEDANTIC],
 [AC_REQUIRE([AC_PROG_CXX])dnl
 AC_LANG_PUSH(C++)
 m4_pushdef([acx_Var], [m4_default([$2], [WARN_PEDANTIC])])dnl
 AC_SUBST(acx_Var)dnl
 m4_expand_once([acx_Var=
 ],m4_quote(acx_Var=))dnl
 # Do the check with the no- prefix removed from the warning options
 # since gcc silently accepts any -Wno-* option on purpose
 m4_pushdef([acx_Woptions], [m4_bpatsubst([$1], [-Wno-], [-W])])dnl
 AS_VAR_PUSHDEF([acx_Pedantic], [acx_cv_prog_cc_pedantic_]acx_Woptions)dnl
 AS_IF([test "$GXX" = yes],
 [AC_CACHE_CHECK([whether $CXX supports -pedantic ]acx_Woptions, acx_Pedantic,
 [save_CXXFLAGS="$CXXFLAGS"
 CXXFLAGS="-pedantic acx_Woptions"
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
    [AS_VAR_SET(acx_Pedantic, yes)],
    [AS_VAR_SET(acx_Pedantic, no)])
 CXXFLAGS="$save_CXXFLAGS"])
 AS_IF([test AS_VAR_GET(acx_Pedantic) = yes],
       [acx_Var="$acx_Var${acx_Var:+ }-pedantic $1"])
 ])
 AS_VAR_POPDEF([acx_Pedantic])dnl
 m4_popdef([acx_Woptions])dnl
 m4_popdef([acx_Var])dnl
 AC_LANG_POP(C++)
 ])# ACX_PROG_CXX_WARNING_ALMOST_PEDANTIC

 # ACX_PROG_CXX_WARNINGS_ARE_ERRORS([x.y.z], [VARIABLE = WERROR])
 #   sets @VARIABLE@ to "-Werror" if the compiler is G++ >=x.y.z, or if
 #   --enable-werror-always was given on the command line, otherwise
 #   to nothing.
 #   If the argument is the word "manual" instead of a version number,
 #   then @VARIABLE@ will be set to -Werror only if --enable-werror-always
 #   appeared on the configure command line.
 AC_DEFUN([ACX_PROG_CXX_WARNINGS_ARE_ERRORS],
 [AC_REQUIRE([AC_PROG_CXX])dnl
 AC_LANG_PUSH(C++)
 m4_pushdef([acx_Var], [m4_default([$2], [WERROR])])dnl
 AC_SUBST(acx_Var)dnl
 m4_expand_once([acx_Var=
 ],m4_quote(acx_Var=))dnl
 AC_ARG_ENABLE(werror-always,
     AS_HELP_STRING([--enable-werror-always],
 		   [enable -Werror despite compiler version]),
 [], [enable_werror_always=no])
 AS_IF([test $enable_werror_always = yes],
       [acx_Var="$acx_Var${acx_Var:+ }-Werror"])
  m4_if($1, [manual],,
  [AS_VAR_PUSHDEF([acx_GXXvers], [acx_cv_prog_cxx_gxx_$1_or_newer])dnl
   AC_CACHE_CHECK([whether $CXX is G++ >=$1], acx_GXXvers,
     [set fnord `echo $1 | tr '.' ' '`
      shift
      AC_PREPROC_IFELSE(
 [#if __GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__ \
   < [$]1 * 10000 + [$]2 * 100 + [$]3
 #error insufficient
 #endif],
    [AS_VAR_SET(acx_GXXvers, yes)],
    [AS_VAR_SET(acx_GXXvers, no)])])
  AS_IF([test AS_VAR_GET(acx_GXXvers) = yes],
        [acx_Var="$acx_Var${acx_Var:+ }-Werror"])
   AS_VAR_POPDEF([acx_GXXvers])])
 m4_popdef([acx_Var])dnl
 AC_LANG_POP(C++)
 ])# ACX_PROG_CXX_WARNINGS_ARE_ERRORS
	# Autoconf include file defining macros related to compile-time warnings.

	# Copyright 2004, 2005, 2007, 2009, 2011 Free Software Foundation, Inc.

	#This file is part of GCC.

	#GCC is free software; you can redistribute it and/or modify it under
	#the terms of the GNU General Public License as published by the Free
	#Software Foundation; either version 3, or (at your option) any later
	#version.

	#GCC is distributed in the hope that it will be useful, but WITHOUT
	#ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	#FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	#for more details.

	#You should have received a copy of the GNU General Public License
	#along with GCC; see the file COPYING3. If not see
	#<http://www.gnu.org/licenses/>.

	# ACX_PROG_CC_WARNING_OPTS(WARNINGS, [VARIABLE = WARN_CFLAGS])
	# Sets @VARIABLE@ to the subset of the given options which the
	# compiler accepts.
	AC_DEFUN([ACX_PROG_CC_WARNING_OPTS],
	[AC_REQUIRE([AC_PROG_CC])dnl
	AC_LANG_PUSH(C)
	m4_pushdef([acx_Var], [m4_default([$2], [WARN_CFLAGS])])dnl
	AC_SUBST(acx_Var)dnl
	m4_expand_once([acx_Var=
	],m4_quote(acx_Var=))dnl
	save_CFLAGS="$CFLAGS"
	for real_option in $1; do
	# Do the check with the no- prefix removed since gcc silently
	# accepts any -Wno-* option on purpose
	case $real_option in
	-Wno-) option=-W`expr x$real_option : 'x-Wno-\(.\)'` ;;
	*) option=$real_option ;;
	esac
	AS_VAR_PUSHDEF([acx_Woption], [acx_cv_prog_cc_warning_$option])
	AC_CACHE_CHECK([whether $CC supports $option], acx_Woption,
	[CFLAGS="$option"
	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
	[AS_VAR_SET(acx_Woption, yes)],
	[AS_VAR_SET(acx_Woption, no)])
	])
	AS_IF([test AS_VAR_GET(acx_Woption) = yes],
	[acx_Var="$acx_Var${acx_Var:+ }$real_option"])
	AS_VAR_POPDEF([acx_Woption])dnl
	done
	CFLAGS="$save_CFLAGS"
	m4_popdef([acx_Var])dnl
	AC_LANG_POP(C)
	])# ACX_PROG_CC_WARNING_OPTS

	# ACX_PROG_CC_WARNING_ALMOST_PEDANTIC(WARNINGS, [VARIABLE = WARN_PEDANTIC])
	# Append to VARIABLE "-pedantic" + the argument, if the compiler is GCC
	# and accepts all of those options simultaneously, otherwise to nothing.
	AC_DEFUN([ACX_PROG_CC_WARNING_ALMOST_PEDANTIC],
	[AC_REQUIRE([AC_PROG_CC])dnl
	AC_LANG_PUSH(C)
	m4_pushdef([acx_Var], [m4_default([$2], [WARN_PEDANTIC])])dnl
	AC_SUBST(acx_Var)dnl
	m4_expand_once([acx_Var=
	],m4_quote(acx_Var=))dnl
	# Do the check with the no- prefix removed from the warning options
	# since gcc silently accepts any -Wno-* option on purpose
	m4_pushdef([acx_Woptions], [m4_bpatsubst([$1], [-Wno-], [-W])])dnl
	AS_VAR_PUSHDEF([acx_Pedantic], [acx_cv_prog_cc_pedantic_]acx_Woptions)dnl
	AS_IF([test "$GCC" = yes],
	[AC_CACHE_CHECK([whether $CC supports -pedantic ]acx_Woptions, acx_Pedantic,
	[save_CFLAGS="$CFLAGS"
	CFLAGS="-pedantic acx_Woptions"
	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
	[AS_VAR_SET(acx_Pedantic, yes)],
	[AS_VAR_SET(acx_Pedantic, no)])
	CFLAGS="$save_CFLAGS"])
	AS_IF([test AS_VAR_GET(acx_Pedantic) = yes],
	[acx_Var="$acx_Var${acx_Var:+ }-pedantic $1"])
	])
	AS_VAR_POPDEF([acx_Pedantic])dnl
	m4_popdef([acx_Woptions])dnl
	m4_popdef([acx_Var])dnl
	AC_LANG_POP(C)
	])# ACX_PROG_CC_WARNING_ALMOST_PEDANTIC

	# ACX_PROG_CC_WARNINGS_ARE_ERRORS([x.y.z], [VARIABLE = WERROR])
	# sets @VARIABLE@ to "-Werror" if the compiler is GCC >=x.y.z, or if
	# --enable-werror-always was given on the command line, otherwise
	# to nothing.
	# If the argument is the word "manual" instead of a version number,
	# then @VARIABLE@ will be set to -Werror only if --enable-werror-always
	# appeared on the configure command line.
	AC_DEFUN([ACX_PROG_CC_WARNINGS_ARE_ERRORS],
	[AC_REQUIRE([AC_PROG_CC])dnl
	AC_LANG_PUSH(C)
	m4_pushdef([acx_Var], [m4_default([$2], [WERROR])])dnl
	AC_SUBST(acx_Var)dnl
	m4_expand_once([acx_Var=
	],m4_quote(acx_Var=))dnl
	AC_ARG_ENABLE(werror-always,
	AS_HELP_STRING([--enable-werror-always],
	[enable -Werror despite compiler version]),
	[], [enable_werror_always=no])
	AS_IF([test $enable_werror_always = yes],
	[acx_Var="$acx_Var${acx_Var:+ }-Werror"])
	m4_if($1, [manual],,
	[AS_VAR_PUSHDEF([acx_GCCvers], [acx_cv_prog_cc_gcc_$1_or_newer])dnl
	AC_CACHE_CHECK([whether $CC is GCC >=$1], acx_GCCvers,
	[set fnord `echo $1 \| tr '.' ' '`
	shift
	AC_PREPROC_IFELSE(
	[#if __GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__ \
	< [$]1 * 10000 + [$]2 * 100 + [$]3
	#error insufficient
	#endif],
	[AS_VAR_SET(acx_GCCvers, yes)],
	[AS_VAR_SET(acx_GCCvers, no)])])
	AS_IF([test AS_VAR_GET(acx_GCCvers) = yes],
	[acx_Var="$acx_Var${acx_Var:+ }-Werror"])
	AS_VAR_POPDEF([acx_GCCvers])])
	m4_popdef([acx_Var])dnl
	AC_LANG_POP(C)
	])# ACX_PROG_CC_WARNINGS_ARE_ERRORS

	# ACX_PROG_CXX_WARNING_OPTS(WARNINGS, [VARIABLE = WARN_CXXFLAGS])
	# Sets @VARIABLE@ to the subset of the given options which the
	# compiler accepts.
	AC_DEFUN([ACX_PROG_CXX_WARNING_OPTS],
	[AC_REQUIRE([AC_PROG_CXX])dnl
	AC_LANG_PUSH(C++)
	m4_pushdef([acx_Var], [m4_default([$2], [WARN_CXXFLAGS])])dnl
	AC_SUBST(acx_Var)dnl
	m4_expand_once([acx_Var=
	],m4_quote(acx_Var=))dnl
	save_CXXFLAGS="$CXXFLAGS"
	for real_option in $1; do
	# Do the check with the no- prefix removed since gcc silently
	# accepts any -Wno-* option on purpose
	case $real_option in
	-Wno-) option=-W`expr x$real_option : 'x-Wno-\(.\)'` ;;
	*) option=$real_option ;;
	esac
	AS_VAR_PUSHDEF([acx_Woption], [acx_cv_prog_cc_warning_$option])
	AC_CACHE_CHECK([whether $CXX supports $option], acx_Woption,
	[CXXFLAGS="$option"
	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
	[AS_VAR_SET(acx_Woption, yes)],
	[AS_VAR_SET(acx_Woption, no)])
	])
	AS_IF([test AS_VAR_GET(acx_Woption) = yes],
	[acx_Var="$acx_Var${acx_Var:+ }$real_option"])
	AS_VAR_POPDEF([acx_Woption])dnl
	done
	CXXFLAGS="$save_CXXFLAGS"
	m4_popdef([acx_Var])dnl
	AC_LANG_POP(C++)
	])# ACX_PROG_CXX_WARNING_OPTS

	# ACX_PROG_CXX_WARNING_ALMOST_PEDANTIC(WARNINGS, [VARIABLE = WARN_PEDANTIC])
	# Append to VARIABLE "-pedantic" + the argument, if the compiler is G++
	# and accepts all of those options simultaneously, otherwise to nothing.
	AC_DEFUN([ACX_PROG_CXX_WARNING_ALMOST_PEDANTIC],
	[AC_REQUIRE([AC_PROG_CXX])dnl
	AC_LANG_PUSH(C++)
	m4_pushdef([acx_Var], [m4_default([$2], [WARN_PEDANTIC])])dnl
	AC_SUBST(acx_Var)dnl
	m4_expand_once([acx_Var=
	],m4_quote(acx_Var=))dnl
	# Do the check with the no- prefix removed from the warning options
	# since gcc silently accepts any -Wno-* option on purpose
	m4_pushdef([acx_Woptions], [m4_bpatsubst([$1], [-Wno-], [-W])])dnl
	AS_VAR_PUSHDEF([acx_Pedantic], [acx_cv_prog_cc_pedantic_]acx_Woptions)dnl
	AS_IF([test "$GXX" = yes],
	[AC_CACHE_CHECK([whether $CXX supports -pedantic ]acx_Woptions, acx_Pedantic,
	[save_CXXFLAGS="$CXXFLAGS"
	CXXFLAGS="-pedantic acx_Woptions"
	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
	[AS_VAR_SET(acx_Pedantic, yes)],
	[AS_VAR_SET(acx_Pedantic, no)])
	CXXFLAGS="$save_CXXFLAGS"])
	AS_IF([test AS_VAR_GET(acx_Pedantic) = yes],
	[acx_Var="$acx_Var${acx_Var:+ }-pedantic $1"])
	])
	AS_VAR_POPDEF([acx_Pedantic])dnl
	m4_popdef([acx_Woptions])dnl
	m4_popdef([acx_Var])dnl
	AC_LANG_POP(C++)
	])# ACX_PROG_CXX_WARNING_ALMOST_PEDANTIC

	# ACX_PROG_CXX_WARNINGS_ARE_ERRORS([x.y.z], [VARIABLE = WERROR])
	# sets @VARIABLE@ to "-Werror" if the compiler is G++ >=x.y.z, or if
	# --enable-werror-always was given on the command line, otherwise
	# to nothing.
	# If the argument is the word "manual" instead of a version number,
	# then @VARIABLE@ will be set to -Werror only if --enable-werror-always
	# appeared on the configure command line.
	AC_DEFUN([ACX_PROG_CXX_WARNINGS_ARE_ERRORS],
	[AC_REQUIRE([AC_PROG_CXX])dnl
	AC_LANG_PUSH(C++)
	m4_pushdef([acx_Var], [m4_default([$2], [WERROR])])dnl
	AC_SUBST(acx_Var)dnl
	m4_expand_once([acx_Var=
	],m4_quote(acx_Var=))dnl
	AC_ARG_ENABLE(werror-always,
	AS_HELP_STRING([--enable-werror-always],
	[enable -Werror despite compiler version]),
	[], [enable_werror_always=no])
	AS_IF([test $enable_werror_always = yes],
	[acx_Var="$acx_Var${acx_Var:+ }-Werror"])
	m4_if($1, [manual],,
	[AS_VAR_PUSHDEF([acx_GXXvers], [acx_cv_prog_cxx_gxx_$1_or_newer])dnl
	AC_CACHE_CHECK([whether $CXX is G++ >=$1], acx_GXXvers,
	[set fnord `echo $1 \| tr '.' ' '`
	shift
	AC_PREPROC_IFELSE(
	[#if __GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__ \
	< [$]1 * 10000 + [$]2 * 100 + [$]3
	#error insufficient
	#endif],
	[AS_VAR_SET(acx_GXXvers, yes)],
	[AS_VAR_SET(acx_GXXvers, no)])])
	AS_IF([test AS_VAR_GET(acx_GXXvers) = yes],
	[acx_Var="$acx_Var${acx_Var:+ }-Werror"])
	AS_VAR_POPDEF([acx_GXXvers])])
	m4_popdef([acx_Var])dnl
	AC_LANG_POP(C++)
	])# ACX_PROG_CXX_WARNINGS_ARE_ERRORS