configfiles=$(wildcard $(srctree)/kernel/configs/$(1).config $(srctree)/arch/$(SRCARCH)/configs/$(1).config)
define mergeconfig
-$(if $(wildcard $(objtree)/.config),, $(error You need an existing .config for this target))
$(if $(call configfiles,$(1)),, $(error No configuration exists for this target on this architecture))
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh -m -O $(objtree) $(objtree)/.config $(call configfiles,$(1))
+$(Q)yes "" | $(MAKE) -f $(srctree)/Makefile oldconfig