diff --git a/sysdeps/m68k/__longjmp.c b/sysdeps/m68k/__longjmp.c
index c00337c5f0..cff37bcf9e 100644
--- a/sysdeps/m68k/__longjmp.c
+++ b/sysdeps/m68k/__longjmp.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991 Free Software Foundation, Inc.
+/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
 This file is part of the GNU C Library.
 
 The GNU C Library is free software; you can redistribute it and/or
@@ -20,6 +20,10 @@ Cambridge, MA 02139, USA.  */
 #include <setjmp.h>
 #include <stdlib.h>
 
+#ifndef	__GNUC__
+  #error This file uses GNU C extensions; you must compile with GCC.
+#endif
+
 /* Jump to the position specified by ENV, causing the
    setjmp call there to return VAL, or 1 if VAL is 0.  */
 __NORETURN