diff --git a/share/mk/bsd.sys.mk b/share/mk/bsd.sys.mk
index 68275a110d7c..27053623b9db 100644
--- a/share/mk/bsd.sys.mk
+++ b/share/mk/bsd.sys.mk
@@ -1,9 +1,13 @@
-#	$NetBSD: bsd.sys.mk,v 1.2 1995/12/13 01:25:07 cgd Exp $
+#	$NetBSD: bsd.sys.mk,v 1.3 1996/05/15 19:46:51 scottr Exp $
 #
 # Overrides used for NetBSD source tree builds.
 
 CFLAGS+= -Werror
 
+.if defined(DESTDIR)
+CFLAGS+= -nostdinc -idirafter ${DESTDIR}/usr/include
+.endif
+
 .if defined(PARALLEL)
 # Lex
 .l: