diff --git a/Makefile.inc1 b/Makefile.inc1
index 07b2f49a17c1..cf11efff49da 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -200,7 +200,7 @@ TMAKEENV=	MAKEOBJDIRPREFIX=${OBJTREE} \
 		DESTDIR= \
 		INSTALL="sh ${.CURDIR}/tools/install.sh"
 TMAKE=		${TMAKEENV} ${MAKE} -f Makefile.inc1 \
-		BOOTSTRAPPING=${OSRELDATE} -DNO_CPU_CFLAGS
+		BOOTSTRAPPING=${OSRELDATE} -DNO_CPU_CFLAGS -DNO_WARNS
 
 # cross-tool stage
 XMAKE=		TOOLS_PREFIX=${WORLDTMP} ${BMAKE} -DNO_FORTRAN -DNO_GDB