recipe for target 'ninja_wrapper' failed

编译Android 7.0以上的源码时须要用到Jack Server，编译过程有可能出现一下错误：

1 error generated. [ 43% 29709/68905] build camscope-autogen ninja: build stopped: subcommand failed. build/core/ninja.mk:148: recipe for target 'ninja_wrapper' failed make: *** [ninja_wrapper] Error 1

这个错误若是是因为Java VM内存不足致使的（上面会有out fo memory提示），解决：

1. export JACK_SERVER_VM_ARGUMENTS="-Dfile.encoding=UTF-8 -XX:+TieredCompilation -Xmx4096m"  
2. prebuilts/sdk/tools/jack-admin kill-server  
3. prebuilts/sdk/tools/jack-admin start-server

不过建议编译机器的内存大于8G。