lastword = $(word $(words $(1)),$(1))
makedir := $(dir $(call lastword,$(MAKEFILE_LIST)))

MAKEARGS := -C ../buildroot BR2_EXTERNAL_DIRS="../rootfs"
MAKEARGS += O=$(if $(patsubst /%,,$(makedir)),$(CURDIR)/)$(patsubst %/,%,$(makedir))

MAKEFLAGS += --no-print-directory

.PHONY: all $(MAKECMDGOALS)

all	:= $(filter-out Makefile,$(MAKECMDGOALS))

_all:
	$(MAKE) $(MAKEARGS) $(all)

Makefile:;

$(all): _all
	@:

%/: _all
	@: