# =========================================================================== # https://www.gnu.org/software/autoconf-archive/ax_check_link_flag.html # =========================================================================== # # SYNOPSIS # # AX_CHECK_LINK_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT]) # # DESCRIPTION # # Check whether the given FLAG works with the linker or gives an error. # (Warnings, however, are ignored) # # ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on # success/failure. # # If EXTRA-FLAGS is defined, it is added to the linker's default flags # when the check is done. The check is thus made with the flags: "LDFLAGS # EXTRA-FLAGS FLAG". This can for example be used to force the linker to # issue an error when a bad flag is given. # # INPUT gives an alternative input source to AC_LINK_IFELSE. # # NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this # macro in sync with AX_CHECK_{PREPROC,COMPILE}_FLAG. # # LICENSE # # Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de> # Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com> # # This program 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 of the License, or (at your # option) any later version. # # This program 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 this program. If not, see <https://www.gnu.org/licenses/>. # # As a special exception, the respective Autoconf Macro's copyright owner # gives unlimited permission to copy, distribute and modify the configure # scripts that are the output of Autoconf when processing the Macro. You # need not follow the terms of the GNU General Public License when using # or distributing such scripts, even though portions of the text of the # Macro appear in them. The GNU General Public License (GPL) does govern # all other use of the material that constitutes the Autoconf Macro. # # This special exception to the GPL applies to versions of the Autoconf # Macro released by the Autoconf Archive. When you make and distribute a # modified version of the Autoconf Macro, you may extend this special # exception to the GPL to apply to your modified version as well. #serial 5 AC_DEFUN([AX_CHECK_LINK_FLAG], [AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_ldflags_$4_$1])dnl AC_CACHE_CHECK([whether the linker accepts $1], CACHEVAR, [ ax_check_save_flags=$LDFLAGS LDFLAGS="$LDFLAGS $4 $1" AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <time.h>]], [[time_t x; int fodder = 0; if (fodder > -1000 && time(&x)) return (int) x]])], [AS_VAR_SET(CACHEVAR,[yes])], [AS_VAR_SET(CACHEVAR,[no])]) LDFLAGS=$ax_check_save_flags]) AS_VAR_IF(CACHEVAR,yes, [m4_default([$2], :)], [m4_default([$3], :)]) AS_VAR_POPDEF([CACHEVAR])dnl ])dnl AX_CHECK_LINK_FLAGS