diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 96cc6c5ec497..d3706a025bad 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: systm.h,v 1.61 1996/11/13 06:07:09 thorpej Exp $	*/
+/*	$NetBSD: systm.h,v 1.62 1996/11/18 05:18:04 jonathan Exp $	*/
 
 /*-
  * Copyright (c) 1982, 1988, 1991, 1993
@@ -68,6 +68,9 @@
  * patched by a stalking hacker.
  */
 
+#ifndef _SYS_SYSTM_H_
+#define _SYS_SYSTM_H_
+
 struct proc;
 struct uio;
 struct tty;
@@ -258,4 +261,6 @@ void	kmstartup __P((void));
 /* debugger entry points */
 void	Debugger __P((void));	/* in DDB only */
 int	read_symtab_from_file __P((struct proc *,struct vnode *,const char *));
-#endif
+#endif	/* DDB */
+
+#endif	/* !_SYS_SYSTM_H_ */