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1# ===========================================================================2# https://www.gnu.org/software/autoconf-archive/ax_check_preproc_flag.html3# ===========================================================================4#5# SYNOPSIS6#7# AX_CHECK_PREPROC_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT])8#9# DESCRIPTION10#11# Check whether the given FLAG works with the current language's12# preprocessor or gives an error. (Warnings, however, are ignored)13#14# ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on15# success/failure.16#17# If EXTRA-FLAGS is defined, it is added to the preprocessor's default18# flags when the check is done. The check is thus made with the flags:19# "CPPFLAGS EXTRA-FLAGS FLAG". This can for example be used to force the20# preprocessor to issue an error when a bad flag is given.21#22# INPUT gives an alternative input source to AC_PREPROC_IFELSE.23#24# NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this25# macro in sync with AX_CHECK_{COMPILE,LINK}_FLAG.26#27# LICENSE28#29# Copyright (c) 2008 Guido U. Draheim <[email protected]>30# Copyright (c) 2011 Maarten Bosmans <[email protected]>31#32# Copying and distribution of this file, with or without modification, are33# permitted in any medium without royalty provided the copyright notice34# and this notice are preserved. This file is offered as-is, without any35# warranty.37#serial 639AC_DEFUN([AX_CHECK_PREPROC_FLAG],40[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF41AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]cppflags_$4_$1])dnl42AC_CACHE_CHECK([whether _AC_LANG preprocessor accepts $1], CACHEVAR, [43ax_check_save_flags=$CPPFLAGS44CPPFLAGS="$CPPFLAGS $4 $1"45AC_PREPROC_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],46[AS_VAR_SET(CACHEVAR,[yes])],47[AS_VAR_SET(CACHEVAR,[no])])48CPPFLAGS=$ax_check_save_flags])49AS_VAR_IF(CACHEVAR,yes,50[m4_default([$2], :)],51[m4_default([$3], :)])52AS_VAR_POPDEF([CACHEVAR])dnl53])dnl AX_CHECK_PREPROC_FLAGS
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