1. 根目录:
2. tools
3. build
4. Makefile

ifeq ($(srctree),)
srctree := $(patsubst %/,%,$(dir $(shell pwd)))
srctree := $(patsubst %/,%,$(dir $(srctree)))
endif

include $(srctree)/tools//scripts/Makefile.include

define allow-override
  $(if $(or $(findstring environment,$(origin $(1))),\
            $(findstring command line,$(origin $(1)))),,\
    $(eval $(1) = $(2)))
endef

$(call allow-override,CC,$(CROSS_COMPILE)gcc)
$(call allow-override,LD,$(CROSS_COMPILE)ld)

ifeq ($(V),1)
  Q =
else
  Q = @
endif

export Q srctree CC LD

MAKEFLAGS := --no-print-directory
build     := -f $(srctree)/tools/build/Makefile.build dir=. obj

all: fixdep

clean:
	$(call QUIET_CLEAN, fixdep)
	$(Q)find . -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
	$(Q)rm -f fixdep

$(OUTPUT)fixdep-in.o: FORCE
	$(Q)$(MAKE) $(build)=fixdep

$(OUTPUT)fixdep: $(OUTPUT)fixdep-in.o
	$(QUIET_LINK)$(CC) $(LDFLAGS) -o $@ $<

FORCE:

.PHONY: FORCE