From 7812d88c95e10e690c3d1c057ab2fa7ad1edaafa Mon Sep 17 00:00:00 2001 From: Lucas De Marchi Date: Fri, 14 Sep 2012 11:18:41 -0300 Subject: [PATCH] build-sys: Append -Werror when testing flags Clang doesn't treat unknown warnings flags as an error, but rather as a warning. The result is that the detection for whic CFLAGS are supported by this compiler will not work, since the compilation will succeed. With this patch we now successfully detect clang doesn't support -Wlogical-op, as opposed to previous behavior: checking if clang supports flag -Wlogical-op in envvar CFLAGS... no We use this macro only for LDFLAGS and CFLAGS, so it's safe to stash -Werror there. --- m4/attributes.m4 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/m4/attributes.m4 b/m4/attributes.m4 index c80ae62..e822197 100644 --- a/m4/attributes.m4 +++ b/m4/attributes.m4 @@ -40,7 +40,7 @@ AC_DEFUN([CC_CHECK_FLAG_APPEND], [ AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2], AS_TR_SH([cc_cv_$2_$3]), [eval "AS_TR_SH([cc_save_$2])='${$2}'" - eval "AS_TR_SH([$2])='$3'" + 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'"]) -- 2.7.4