My Xcode is up-to-date. I try to execute sudo pip install pil, but I get this error:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/tk.h:78:11: fatal error: 'X11/Xlib.h' file not found
# include <X11/Xlib.h>
^
1 error generated.
error: command 'cc' failed with exit status 1
Solution:
ln -s /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/System/Library/Frameworks/Tk.framework/Versions/8.5/Headers/X11 /usr/local/include/X11
sudo pip install pil