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-rw-r--r--m4/attributes.m413
1 files changed, 8 insertions, 5 deletions
diff --git a/m4/attributes.m4 b/m4/attributes.m4
index 4b0fcdce3d..db5df250f4 100644
--- a/m4/attributes.m4
+++ b/m4/attributes.m4
@@ -35,15 +35,18 @@ dnl well.
dnl Check if FLAG in ENV-VAR is supported by compiler and append it
dnl to WHERE-TO-APPEND variable. Note that we invert -Wno-* checks to
-dnl -W* as gcc cannot test for negated warnings.
-dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG])
+dnl -W* as gcc cannot test for negated warnings. If a C snippet is passed,
+dnl use it, otherwise use a simple main() definition that just returns 0.
+dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG], [C-SNIPPET])
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])='-Werror `echo "$3" | sed 's/^-Wno-/-W/'`'"
- AC_LINK_IFELSE([AC_LANG_SOURCE([int main(void) { return 0; } ])],
+ AC_LINK_IFELSE([AC_LANG_SOURCE(ifelse([$4], [],
+ [int main(void) { return 0; } ],
+ [$4]))],
[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'"])
@@ -52,10 +55,10 @@ AC_DEFUN([CC_CHECK_FLAG_APPEND], [
[eval "$1='${$1} $3'"])
])
-dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2])
+dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2], [C-SNIPPET])
AC_DEFUN([CC_CHECK_FLAGS_APPEND], [
for flag in [$3]; do
- CC_CHECK_FLAG_APPEND([$1], [$2], $flag)
+ CC_CHECK_FLAG_APPEND([$1], [$2], $flag, [$4])
done
])