diff -Naur vhba-module-1.2.1.orig/Makefile vhba-module-1.2.1/Makefile
--- vhba-module-1.2.1.orig/Makefile	2009-09-19 13:10:07.790478925 +0200
+++ vhba-module-1.2.1/Makefile	2009-09-19 13:16:03.484646317 +0200
@@ -9,7 +9,7 @@
 ifndef KERNELRELEASE
 	KERNELRELEASE := `uname -r`
 endif
-KDIR := /lib/modules/$(KERNELRELEASE)/build
+KDIR ?= /lib/modules/$(KERNELRELEASE)/build
 KMAKE := $(MAKE) -C $(KDIR) M=$(PWD)
 
 all: kernel.api.h modules