运行时brew doctor
出现此错误
Warning: Your compilers are different from the standard versions for your Xcode.
If you have Xcode 4.3 or newer, you should install the Command Line Tools for
Xcode from within Xcode's Download preferences.
Otherwise, you should reinstall Xcode.
我已经多次重新安装了 xcode,并且每次都重新安装了 cli 工具。