diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index dca175fffcab..4b4e8e136ce6 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -218,6 +218,6 @@ endif
 #
 ifneq ($(findstring e, $(KBUILD_EXTRA_WARN)),)
 
-KBUILD_CFLAGS += -Werror
+KBUILD_CPPFLAGS		+= -Werror
 
 endif