1.今天 当我  执行  git add  somefile 的时候，出现 如下 错误：

If no other git process is currently running, this probably means a

git process crashed in this repository earlier. Make sure no other git

process is running and remove the file manually to continue.

解决方法：

rm -f ./.git/index.lock

2. 编译ICS时 出现 如下错误：

build/core/java.mk:20: *** dalvik/dexgen: Invalid LOCAL_SDK_VERSION '4' Choices are: current .  Stop.

解决方法：

rm -rf prebuilt ; repo sync prebuilt