diff --git a/drivers/bios_emulator/Makefile b/drivers/bios_emulator/Makefile
index dd9c102ba85bba37f6a1b8ca5cb9bab106d28698..feba4da758975086a52a1fe2ca317e00f726b80c 100644
--- a/drivers/bios_emulator/Makefile
+++ b/drivers/bios_emulator/Makefile
@@ -23,6 +23,7 @@ EXTRA_CFLAGS += -I. -I./include -I$(TOPDIR)/include \
 
 CFLAGS += $(EXTRA_CFLAGS)
 HOSTCFLAGS += $(EXTRA_CFLAGS)
+CPPFLAGS += $(EXTRA_CFLAGS)
 
 all:	$(LIB)