diff -Naur a/Makefile b/Makefile
--- a/Makefile	2016-09-15 11:26:43.100694462 -0700
+++ b/Makefile	2016-09-15 11:28:32.074066323 -0700
@@ -35,7 +35,7 @@
 WFLAGS := -Wall -Wstrict-prototypes  -Wmissing-prototypes
 WFLAGS += -Wmissing-declarations -Wold-style-definition -Wformat=2
 
-CFLAGS = $(WFLAGS) $(CCOPTS) -I../include $(DEFINES)
+CFLAGS = $(WFLAGS) $(CCOPTS) -I../include $(if $(KERNEL_INCLUDE),-I$(KERNEL_INCLUDE)) $(DEFINES)
 YACCFLAGS = -d -t -v
 
 SUBDIRS=lib ip tc bridge misc netem genl man