diff --git a/Makefile b/Makefile
index 0bc4891..bd1488a 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ OBJS	+= kvm.o
 OBJS	+= main.o
 OBJS	+= util.o
 
-CFLAGS	+= -Iinclude
+CFLAGS	+= $(CPPFLAGS) -Iinclude
 
 WARNINGS += -Wall
 WARNINGS += -Wcast-align