dnl well.
dnl Check if FLAG in ENV-VAR is supported by compiler and append it
-dnl to WHERE-TO-APPEND variable
-dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG])
+dnl to WHERE-TO-APPEND variable. Note that we invert -Wno-* checks to
+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 $3'"
- AC_LINK_IFELSE([AC_LANG_SOURCE([int main(void) { return 0; } ])],
+ eval "AS_TR_SH([$2])='${cc_save_$2} -Werror `echo "$3" | sed 's/^-Wno-/-W/'`'"
+ 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'"])
[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)
+ for flag in [$3]; do
+ CC_CHECK_FLAG_APPEND([$1], [$2], $flag, [$4])
done
])
*-freebsd* | *-openbsd*) ;;
*)
dnl First of all check for the --no-undefined variant of GNU ld. This allows
- dnl for a much more readable commandline, so that people can understand what
+ dnl for a much more readable command line, so that people can understand what
dnl it does without going to look for what the heck -z defs does.
for possible_flags in "-Wl,--no-undefined" "-Wl,-z,defs"; do
CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"])