diff --git a/lkm/nullfs/Makefile b/lkm/nullfs/Makefile
index 9f7cd12ca7c5..dae6d79ba5ee 100644
--- a/lkm/nullfs/Makefile
+++ b/lkm/nullfs/Makefile
@@ -1,10 +1,14 @@
-#	$Id$
+#	$Id: Makefile,v 1.3 1997/02/22 12:48:43 peter Exp $
 
 .PATH:	${.CURDIR}/../../sys/miscfs/nullfs
 KMOD=	null_mod
-SRCS=	null_subr.c null_vfsops.c null_vnops.c
+SRCS=	null_subr.c null_vfsops.c null_vnops.c opt_debug_nullfs.h
 NOMAN=
 VFS_LKM=
 CFLAGS+= -DNULLFS
+CLEANFILES=	opt_debug_nullfs.h
+
+opt_debug_nullfs.h:
+		touch ${.TARGET}
 
 .include <bsd.kmod.mk>
diff --git a/sys/modules/nullfs/Makefile b/sys/modules/nullfs/Makefile
index 9f7cd12ca7c5..dae6d79ba5ee 100644
--- a/sys/modules/nullfs/Makefile
+++ b/sys/modules/nullfs/Makefile
@@ -1,10 +1,14 @@
-#	$Id$
+#	$Id: Makefile,v 1.3 1997/02/22 12:48:43 peter Exp $
 
 .PATH:	${.CURDIR}/../../sys/miscfs/nullfs
 KMOD=	null_mod
-SRCS=	null_subr.c null_vfsops.c null_vnops.c
+SRCS=	null_subr.c null_vfsops.c null_vnops.c opt_debug_nullfs.h
 NOMAN=
 VFS_LKM=
 CFLAGS+= -DNULLFS
+CLEANFILES=	opt_debug_nullfs.h
+
+opt_debug_nullfs.h:
+		touch ${.TARGET}
 
 .include <bsd.kmod.mk>