From: David Herrmann <dh.herrmann@gmail.com>
Date: Fri, 13 Sep 2013 10:42:12 +0000 (+0200)
Subject: from systemd: build: check for build/link flags harder
X-Git-Tag: v20~19
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=779729cf535549bfd687227da2385b607cc31a61;p=thirdparty%2Fkmod.git

from systemd: build: check for build/link flags harder

Use AC_LINK_IFELSE instead of AC_COMPILE_IFELSE to test for flags that
might succeed during compilation but not during linking. An example is gcc
compiled with libssp support but gnu-ld without it. In this case
-fstack-protector works fine during compilation but fails during linking
as several internal helpers are missing.
---

diff --git a/m4/attributes.m4 b/m4/attributes.m4
index 104f04ce..fad1c8f0 100644
--- a/m4/attributes.m4
+++ b/m4/attributes.m4
@@ -42,9 +42,9 @@ AC_DEFUN([CC_CHECK_FLAG_APPEND], [
                  AS_TR_SH([cc_cv_$2_$3]),
                  [eval "AS_TR_SH([cc_save_$2])='${$2}'"
                   eval "AS_TR_SH([$2])='-Werror $3'"
-                  AC_COMPILE_IFELSE([AC_LANG_SOURCE([int a = 0; int main(void) { return a; } ])],
-                                    [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
-                                    [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
+                  AC_LINK_IFELSE([AC_LANG_SOURCE([int a = 0; int main(void) { return a; } ])],
+                          [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
+                          [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
                   eval "AS_TR_SH([$2])='$cc_save_$2'"])
 
   AS_IF([eval test x$]AS_TR_SH([cc_cv_$2_$3])[ = xyes],