diff --git a/sys/arch/vax/conf/Makefile.vax b/sys/arch/vax/conf/Makefile.vax
index cf572e4ab45d..ba04c06ccb5c 100644
--- a/sys/arch/vax/conf/Makefile.vax
+++ b/sys/arch/vax/conf/Makefile.vax
@@ -1,4 +1,4 @@
-#	$NetBSD: Makefile.vax,v 1.11 1995/07/24 18:58:32 ragge Exp $
+#	$NetBSD: Makefile.vax,v 1.12 1995/09/19 23:57:55 thorpej Exp $
 
 #	@(#)Makefile.vax	7.18 (Berkeley) 12/16/90
 #
@@ -30,7 +30,7 @@ VAX=	../..
 INCLUDES= -I. -I$S/arch -I$S -I$S/sys
 COPTS=	${INCLUDES} ${IDENT} -D_KERNEL -D_VAX_INLINE_
 AOPTS=  ${COPTS} -DASSEMBLER
-CFLAGS=	${COPTS}
+CFLAGS=	-Werror -fno-builtin ${COPTS}
 LOAD_ADDRESS=80000000
 
 ### find out what to use for libkern