android :
error-------------------------------------------------------------
make: Entering directory '/home/*/android_code/linux/kernel’
make[1]: Entering directory ‘/home/***/android_code/out/target/product/spectralite/linux/kernel’
CHK include/config/kernel.release
GEN ./Makefile
CHK include/generated/uapi/linux/version.h
Using /home//***//android_code/linux/kernel as source for kernel
/home//***//android_code/linux/kernel is not clean, please run ‘make mrproper’
in the ‘/home//***//android_code/linux/kernel’ directory.
/home//***//android_code/linux/kernel/Makefile:969: recipe for target ‘prepare3’ failed
make[1]: *** [prepare3] Error 1
make[1]: *** Waiting for unfinished jobs…
make[1]: *** wait: No child processes. Stop.
Makefile:146: recipe for target ‘sub-make’ failed
make: *** [sub-make] Error 2
make: Leaving directory ‘/home//***//android_code/linux/kernel’
[ 38% 56/147] Ensure Jack server is installed and started
Jack server already installed in "/home//*//.jack-server"
Server is already running
ninja: build stopped: subcommand failed.
build/core/ninja.mk:148: recipe for target ‘ninja_wrapper’ failed
make: *** [ninja_wrapper] Error 1
make failed to build some targets (12:57 (mm:ss))
为 Android 工程编译内核失败，报错信息为：
kernel/ is not clean, please run 'make mrproper'
于是执行 make mrproper 命令，但又报错找不到 mrproper 目标。
其实我们这时如果在 kernel/Makefile 文件中搜索 "is not clean" 字符串，
就可以找到下面这段代码：
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;
endif
这时我们就可以看到，当 kernel/ 目录下存在 .config 文件或在 kernel/include/ 目录下存在 config/ 目录时，shell 就会打印本段开头看到的错误信息并退出。相应的，问题的解决方法就是删除这 2 个对象。 进入 kernel/ 目录下查找，不存在 .config 文件；再进入 kernel/include/ 目录下查找，果然发现了 config/ 目录！进入该目录查看发现它竟然是空的（一个空的目录竟然能导致整个工程编译失败，果然细节影响成败啊！）。删除掉 config/ 目录后回到 Android 工程顶层，重新执行 source 和 lunch 命令，重新编译。编译通过！
make_ext4fs -s -T -1 -S out/target/product/tb8167p3_bsp/obj/ETC/file_contexts.bin_intermediates/file_contexts.bin -L system -l 2378190848 -a system out/target/product/tb8167p3_bsp/obj/PACKAGING/systemimage_intermediates/system.img out/target/product/tb8167p3_bsp/system out/target/product/tb8167p3_bsp/system
Creating filesystem with parameters:
Size: 2378190848
Block size: 4096
Blocks per group: 32768
Inodes per group: 8080
Inode size: 256
Journal blocks: 9072
Label: system
Blocks: 580613
Block groups: 18
Reserved block group size: 143
Created filesystem with 2432/145440 inodes and 294508/580613 blocks
Running: build_verity_tree -A aee087a5be3b982978c923f566a94613496b417f2af592639bc80d141e34dfe7 out/target/product/tb8167p3_bsp/obj/PACKAGING/systemimage_intermediates/system.img /tmp/tmpUJKQZz_verity_images/verity.img
ae67c59cc47ef1c6617ec24fb8e98cec14dd07bfa7fae6db269e31fa368b96ab aee087a5be3b982978c923f566a94613496b417f2af592639bc80d141e34dfe7
Running: system/extras/verity/build_verity_metadata.py build 2378190848 /tmp/tmpUJKQZz_verity_images/verity_metadata.img ae67c59cc47ef1c6617ec24fb8e98cec14dd07bfa7fae6db269e31fa368b96ab aee087a5be3b982978c923f566a94613496b417f2af592639bc80d141e34dfe7 /dev/block/platform/soc/11120000.mmc/by-name/system verity_signer build/target/product/security/verity.pk8
['verity_signer', '/tmp/tmp0Hmlji.table', 'build/target/product/security/verity.pk8', '/tmp/tmpOLmOqV.sig']
appending /tmp/tmpUJKQZz_verity_images/verity_metadata.img to /tmp/tmpUJKQZz_verity_images/verity.img
Running: fec -e -p 0 out/target/product/tb8167p3_bsp/obj/PACKAGING/systemimage_intermediates/system.img /tmp/tmpUJKQZz_verity_images/verity.img /tmp/tmpUJKQZz_verity_images/verity_fec.img
encoding RS(255, 253) to '/tmp/tmpUJKQZz_verity_images/verity_fec.img' for input files:
1: 'out/target/product/tb8167p3_bsp/obj/PACKAGING/systemimage_intermediates/system.img'
2: '/tmp/tmpUJKQZz_verity_images/verity.img'
appending /tmp/tmpUJKQZz_verity_images/verity_fec.img to /tmp/tmpUJKQZz_verity_images/verity.img
Running: append2simg out/target/product/tb8167p3_bsp/obj/PACKAGING/systemimage_intermediates/system.img /tmp/tmpUJKQZz_verity_images/verity.img
[100% 8867/8867] Install system fs image: out/target/product/tb8167p3_bsp/system.img
out/target/product/tb8167p3_bsp/system.img+out/target/product/tb8167p3_bsp/obj/PACKAGING/recovery_patch_intermediates/recovery_from_boot.p maxsize=2466499200 blocksize=4224 total=1207988115 reserve=24917376
[0;32m#### build completed successfully (16:35 (mm:ss)) ####[00m