在Mac下安装MySQL-python一直有问题，不管是用pip还是用setup.py，都是返回如下错误：
sudo python setup.py install
running install
running bdist_egg
running egg_info
writing MySQL_python.egg-info/PKG-INFO
writing top-level names to MySQL_python.egg-info/top_level.txt
writing dependency_links to MySQL_python.egg-info/dependency_links.txt
reading manifest file 'MySQL_python.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
writing manifest file 'MySQL_python.egg-info/SOURCES.txt'
installing library code to build/bdist.macosx-10.7-x86_64/egg
running install_lib
running build_py
copying MySQLdb/release.py -> build/lib.macosx-10.7-x86_64-2.7/MySQLdb
running build_ext
building '_mysql' extension
/ A p p l i c a t i o n s / X c o d e . a p p / C o n t e n t s / D e v e l o p e r / T o o l c h a i n s / X c o d e D e f a u l t . x c t o o l c h a i n / u s r / b i n / c l a n g - f n o - s t r i c t - a l i a s i n g - f n o - c o m m o n - d y n a m i c - I / u s r / l o c a l / i n c l u d e - I / u s r / l o c a l / o p t / s q l i t e / i n c l u d e - i s y s r o o t / A p p l i c a t i o n s / X c o d e . a p p / C o n t e n t s / D e v e l o p e r / P l a t f o r m s / M a c O S X . p l a t f o r m / D e v e l o p e r / S D K s / M a c O S X 1 0 . 7 . s d k - I / A p p l i c a t i o n s / X c o d e . a p p / C o n t e n t s / D e v e l o p e r / P l a t f o r m s / M a c O S X . p l a t f o r m / D e v e l o p e r / S D K s / M a c O S X 1 0 . 7 . s d k / S y s t e m / L i b r a r y / F r a m e w o r k s / T k . f r a m e w o r k / V e r s i o n s / 8 . 5 / H e a d e r s - D N D E B U G - g - f w r a p v - O 3 - W a l l - W s t r i c t - p r o t o t y p e s -Dversion_info=(1,2,4,'final',1) -D__version__=1.2.4 -I/usr/local/Cellar/mysql/5.6.10/include -I/usr/local/Cellar/python/2.7.5/Frameworks/Python.framework/Versions/2.7/include/python2.7 -c _mysql.c -o build/temp.macosx-10.7-x86_64-2.7/_mysql.o -Os -g -fno-strict-aliasing
unable to execute /: Permission denied
error: command '/' failed with exit status 1
经过Google，发现原来是XCode没有安装Command line Tools的问题，参考：http://sourceforge.net/p/mysql-python/bugs/333/