X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=m4%2Fattribute.m4;fp=m4%2Fattribute.m4;h=58b8346723f1ba7bf7d25c02530da2579f703a4b;hp=0000000000000000000000000000000000000000;hb=da3078c63a3b658573f6e2f986f69ed4d7993b3a;hpb=d798b8b3d832f8c69769e08cfd64a4d8355faf0e

diff --git a/m4/attribute.m4 b/m4/attribute.m4
new file mode 100644
index 00000000..58b83467
--- /dev/null
+++ b/m4/attribute.m4
@@ -0,0 +1,25 @@
+dnl Check to find out whether function attributes are supported.
+dnl If they are not, #define them to be nothing.
+
+AC_DEFUN(tinc_ATTRIBUTE,
+[
+  AC_CACHE_CHECK([for working $1 attribute], tinc_cv_attribute_$1,
+  [ 
+    tempcflags="$CFLAGS"
+    CFLAGS="$CFLAGS -Wall -Werror"
+    AC_COMPILE_IFELSE(
+      [AC_LANG_SOURCE(
+        [void test(void) __attribute__ (($1));
+	 void test(void) { return; }
+	],
+       )],
+       [tinc_cv_attribute_$1=yes],
+       [tinc_cv_attribute_$1=no]
+     )
+     CFLAGS="$tempcflags"
+   ])
+
+   if test ${tinc_cv_attribute_$1} = no; then
+     AC_DEFINE([$1], [], [Defined if the $1 attribute is not supported.])
+   fi
+])