-include $(if $(wildcard $(srctree)/$(src)/Kbuild), \
- $(srctree)/$(src)/Kbuild, $(srctree)/$(src)/Makefile)
+kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
+include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile)