1 files changed, 2 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 5185c917077b..423397f03921 100644
--- a/Makefile
+++ b/Makefile
@@ -203,7 +203,7 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
 
 HOSTCC          = gcc
 HOSTCXX         = g++
-HOSTCFLAGS      = -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer
+HOSTCFLAGS      = -Wall -Wundef -Wstrict-prototypes -O2 -fomit-frame-pointer
 HOSTCXXFLAGS    = -O2
 
 #       Decide whether to build built-in, modular, or both.
@@ -348,7 +348,7 @@ LINUXINCLUDE    := -Iinclude \
 
 CPPFLAGS        := -D__KERNEL__ $(LINUXINCLUDE)
 
-CFLAGS          := -Wall -Wstrict-prototypes -Wno-trigraphs \
+CFLAGS          := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
                    -fno-strict-aliasing -fno-common \
                    -ffreestanding
 AFLAGS          := -D__ASSEMBLY__