This is mostly just preparation for the next patch. But this macro is
used for flags that are only needed during linking but that don't
make sense for normal compilation.
I saw this exact type of patch online for systemd, but it never seems to
have actually been incorporated into their attributes.m4.
---
m4/attributes.m4 | 43 +++++++++++++++++++++++++++++++++++++------
1 files changed, 37 insertions(+), 6 deletions(-)
diff --git a/m4/attributes.m4 b/m4/attributes.m4
index 9d561c2..20d05e4 100644
--- a/m4/attributes.m4
+++ b/m4/attributes.m4
@@ -81,15 +81,14 @@ AC_DEFUN([CC_CHECK_CFLAGS_APPEND], [
done
])
-dnl Check if the flag is supported by linker (cacheable)
-dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
+dnl Check if the flag is supported by linker
+dnl CC_CHECK_LDFLAGS_SILENT([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
-AC_DEFUN([CC_CHECK_LDFLAGS], [
- AC_CACHE_CHECK([if $CC supports $1 flag],
- AS_TR_SH([cc_cv_ldflags_$1]),
+AC_DEFUN([CC_CHECK_LDFLAGS_SILENT], [
+ AC_CACHE_VAL(AS_TR_SH([cc_cv_ldflags_$1]),
[ac_save_LDFLAGS="$LDFLAGS"
LDFLAGS="$LDFLAGS $1"
- AC_LINK_IFELSE([int main() { return 1; }],
+ AC_LINK_IFELSE([AC_LANG_SOURCE([int main() { return 1; }])],
[eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"],
[eval "AS_TR_SH([cc_cv_ldflags_$1])="])
LDFLAGS="$ac_save_LDFLAGS"
@@ -99,6 +98,38 @@ AC_DEFUN([CC_CHECK_LDFLAGS], [
[$2], [$3])
])
+dnl Check if the flag is supported by linker (cacheable)
+dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
+
+AC_DEFUN([CC_CHECK_LDFLAGS], [
+ AC_CACHE_CHECK([if $CC supports $1 flag],
+ AS_TR_SH([cc_cv_ldflags_$1]),
+ CC_CHECK_LDFLAGS_SILENT([$1]) dnl Don't execute actions here!
+ )
+
+ AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
+ [$2], [$3])
+])
+
+dnl CC_CHECK_LDFLAG_APPEND(FLAG, [action-if-found], [action-if-not-found])
+dnl Check for LDFLAG and appends them to LDFLAGS if supported
+AC_DEFUN([CC_CHECK_LDFLAG_APPEND], [
+ AC_CACHE_CHECK([if $CC supports $1 flag],
+ AS_TR_SH([cc_cv_ldflags_$1]),
+ CC_CHECK_LDFLAGS_SILENT([$1]) dnl Don't execute actions here!
+ )
+
+ AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
+ [LDFLAGS="$LDFLAGS $1"; DEBUG_LDFLAGS="$DEBUG_LDFLAGS $1"; $2], [$3])
+])
+
+dnl CC_CHECK_LDFLAGS_APPEND([FLAG1 FLAG2], [action-if-found], [action-if-not])
+AC_DEFUN([CC_CHECK_LDFLAGS_APPEND], [
+ for flag in $1; do
+ CC_CHECK_LDFLAG_APPEND($flag, [$2], [$3])
+ done
+])
+
dnl define the LDFLAGS_NOUNDEFINED variable with the correct value for
dnl the current linker to avoid undefined references in a shared object.
AC_DEFUN([CC_NOUNDEFINED], [
--
1.7.5.4
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