diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h
index 1bc85c6a4676..eaedea995188 100644
--- a/sys/sys/cdefs.h
+++ b/sys/sys/cdefs.h
@@ -113,6 +113,7 @@
  * in a different (wrong) way).
  */
 #if __GNUC__ < 2 || __GNUC__ == 2 && __GNUC_MINOR__ < 5
+#define	__attribute__(x)
 #define	__dead2
 #define	__pure2
 #define	__unused