title: Error installing PyObjc: command '/usr/bin/clang' failed
body: <p>I've been working on a python script, first using the Psychopy compiler, which already included all I needed, but now I need to make it the more independent as possible. I have the script working on a Windows computer, but I also want it to work in OSX.</p>
  
  <p>The script uses pyglet and I followed <a href="http://twistedpairdevelopment.wordpress.com/2012/02/21/installing-pyglet-in-mac-os-x/" rel="nofollow">this post</a> in order to install it. However, when I reach the latest step, which is installing PyObjc, I have the following error:</p>
  
  <pre><code>40 warnings and 1 error generated.
  
  error: command '/usr/bin/clang' failed with exit status 1
  
  ----------------------------------------
  Cleaning up...
  Command /Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python -c "import setuptools, tokenize;__file__='/private/var/folders/fk/1plt8wj53_d183pv59scmg4m0000gn/T/pip_build_JL/pyobjc-core/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/fk/1plt8wj53_d183pv59scmg4m0000gn/T/pip-HfEjaW-record/install-record.txt --single-version-externally-managed --compile failed with error code 1 in /private/var/folders/fk/1plt8wj53_d183pv59scmg4m0000gn/T/pip_build_JL/pyobjc-core
  Storing debug log for failure in /Users/JL/.pip/pip.log
  </code></pre>
  
  <p>Why does this error appears? What can I do to solve it?</p>