1# =========================================================================== 2# https://www.gnu.org/software/autoconf-archive/ax_check_link_flag.html 3# =========================================================================== 4# 5# SYNOPSIS 6# 7# AX_CHECK_LINK_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT]) 8# 9# DESCRIPTION 10# 11# Check whether the given FLAG works with the linker or gives an error. 12# (Warnings, however, are ignored) 13# 14# ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on 15# success/failure. 16# 17# If EXTRA-FLAGS is defined, it is added to the linker's default flags 18# when the check is done. The check is thus made with the flags: "LDFLAGS 19# EXTRA-FLAGS FLAG". This can for example be used to force the linker to 20# issue an error when a bad flag is given. 21# 22# INPUT gives an alternative input source to AC_LINK_IFELSE. 23# 24# NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this 25# macro in sync with AX_CHECK_{PREPROC,COMPILE}_FLAG. 26# 27# LICENSE 28# 29# Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de> 30# Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com> 31# 32# This program is free software: you can redistribute it and/or modify it 33# under the terms of the GNU General Public License as published by the 34# Free Software Foundation, either version 3 of the License, or (at your 35# option) any later version. 36# 37# This program is distributed in the hope that it will be useful, but 38# WITHOUT ANY WARRANTY; without even the implied warranty of 39# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 40# Public License for more details. 41# 42# You should have received a copy of the GNU General Public License along 43# with this program. If not, see <https://www.gnu.org/licenses/>. 44# 45# As a special exception, the respective Autoconf Macro's copyright owner 46# gives unlimited permission to copy, distribute and modify the configure 47# scripts that are the output of Autoconf when processing the Macro. You 48# need not follow the terms of the GNU General Public License when using 49# or distributing such scripts, even though portions of the text of the 50# Macro appear in them. The GNU General Public License (GPL) does govern 51# all other use of the material that constitutes the Autoconf Macro. 52# 53# This special exception to the GPL applies to versions of the Autoconf 54# Macro released by the Autoconf Archive. When you make and distribute a 55# modified version of the Autoconf Macro, you may extend this special 56# exception to the GPL to apply to your modified version as well. 57 58#serial 5 59 60AC_DEFUN([AX_CHECK_LINK_FLAG], 61[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF 62AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_ldflags_$4_$1])dnl 63AC_CACHE_CHECK([whether the linker accepts $1], CACHEVAR, [ 64 ax_check_save_flags=$LDFLAGS 65 LDFLAGS="$LDFLAGS $4 $1" 66 AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], 67 [[time_t x; int fodder = 0; if (fodder > -1000 && time(&x)) return (int) x]])], 68 [AS_VAR_SET(CACHEVAR,[yes])], 69 [AS_VAR_SET(CACHEVAR,[no])]) 70 LDFLAGS=$ax_check_save_flags]) 71AS_VAR_IF(CACHEVAR,yes, 72 [m4_default([$2], :)], 73 [m4_default([$3], :)]) 74AS_VAR_POPDEF([CACHEVAR])dnl 75])dnl AX_CHECK_LINK_FLAGS 76