[Android] 编译出现 xxx is not clean, please run 'make mrproper'

在kernel目录进行过make menuconfig之后，再编译整包出现 xxx is not clean, please run 'make mrproper'报错
但是根据提示在kernel路径下执行 make mrproper，依旧出现错误

这时候去根据提示内容，去找相应的Makefile，看看设么条件下会报这样的错

Makefile位于kernel的根目录下

# prepare3 is used to check if we are building in a separate output directory,
# and if so do:
# 1) Check that make has not been executed in the kernel src $(srctree)
prepare3: include/config/kernel.release
ifneq ($(KBUILD_SRC),)
	@$(kecho) '  Using $(srctree) as source for kernel'
	$(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \
		echo >&2 "  $(srctree) is not clean, please run 'make mrproper'"; \
		echo >&2 "  in the '$(srctree)' directory.";\
		/bin/false; \
	fi;
ndif

也就是会检查kernel根目录下是否有名.config的文件以及include路径下是否存在名为config的目录，如果有就出现" $(srctree) is not clean, please run 'make mrproper'"提示

所以解决这个问题的办法就是删掉 .config 和include/config
继续工作～