diff --git a/doc/HACKS b/doc/HACKS
index 4448c0249f5b..7a48d35ec5d3 100644
--- a/doc/HACKS
+++ b/doc/HACKS
@@ -1,4 +1,4 @@
-# $NetBSD: HACKS,v 1.42 2005/02/22 18:47:09 christos Exp $
+# $NetBSD: HACKS,v 1.43 2005/04/05 11:56:09 tron Exp $
 #
 # This file is intended to document workarounds for currently unsolved
 # (mostly) compiler bugs.
@@ -183,6 +183,15 @@ port	vax
 		Should be reverted when a newer gcc is ready for vax.
 	kcah
 
+	hack	vax gcc 2.95.3 doesn't understand "-std=c99"
+	cdat	5 April 2005
+	who	tron
+	file	src/share/mk/bsd.sys.mk
+	descr
+		We cannot use "-std=c99" for compiler warning level 4 and above
+		because gcc 2.95.3 doesn't support that option.
+	kcah
+
 port	sparc64
 
 	hack	binutil-2.11-sparc64-pltrela
diff --git a/share/mk/bsd.sys.mk b/share/mk/bsd.sys.mk
index f5c749e2f514..0c74c493fbdc 100644
--- a/share/mk/bsd.sys.mk
+++ b/share/mk/bsd.sys.mk
@@ -1,4 +1,4 @@
-#	$NetBSD: bsd.sys.mk,v 1.115 2005/02/20 01:31:44 matt Exp $
+#	$NetBSD: bsd.sys.mk,v 1.116 2005/04/05 11:56:09 tron Exp $
 #
 # Build definitions used for NetBSD source tree builds.
 
@@ -26,7 +26,7 @@ CFLAGS+=	-Wreturn-type -Wswitch -Wshadow
 .if ${WARNS} > 2
 CFLAGS+=	-Wcast-qual -Wwrite-strings
 .endif
-.if ${WARNS} > 3
+.if ${WARNS} > 3 && ${MACHINE_ARCH} != "vax"
 CFLAGS+=	-std=c99
 .endif
 .endif