mac easy_install 安裝插件失敗

Processing psycopg2-2.5.1.tar.gz
Running psycopg2-2.5.1/setup.py -q bdist_egg --dist-dir /tmp/easy_install-ppQtet/psycopg2-2.5.1/egg-dist-tmp-1tmQLX
unable to execute llvm-gcc-4.2: No such file or directory

error: Setup script exited with error: command 'llvm-gcc-4.2' failed with exit status 1

Here's what worked for me:

1. Install the latest version of XCode from the App Store
2. Inside XCode, go to Preferences -> Downloads -> Components
3. download the Command Line Tools