title: Error: No module named psycopg2.extensions
body: <p>I am trying to set up a PostgreSQL database for my django project, which I believe I have done now thanks to the replies to my last question <a href="https://stackoverflow.com/questions/12710715/problems-setting-up-a-postgresql-database-for-a-django-project/12713737#comment17168054_12713737">Problems setting up a postgreSQL database for a django project</a>. I am now trying to run the command 'python manage.py runserver' in Terminal to get my localhost up but when I run the command, I see this response...</p>
  
  <pre><code>Error: No module named psycopg2.extensions
  </code></pre>
  
  <p>I'm not sure what this means - I have tried to download psycopg2 but can't seem to find a way to download psycopg2 using homebrew. I have tried easy_install, pip install and sudo but all return errors like this...</p>
  
  <pre><code>Downloading http://www.psycopg.org/psycopg/tarballs/PSYCOPG-2-4/psycopg2-2.4.5.tar.gz
  Processing psycopg2-2.4.5.tar.gz
  Writing /tmp/easy_install-l7Qi62/psycopg2-2.4.5/setup.cfg
  Running psycopg2-2.4.5/setup.py -q bdist_egg --dist-dir /tmp/easy_install-l7Qi62/psycopg2-2.4.5/egg-dist-tmp-PBP5Ds
  no previously-included directories found matching 'doc/src/_build'
  unable to execute gcc-4.0: No such file or directory
  error: Setup script exited with error: command 'gcc-4.0' failed with exit status 1
  </code></pre>
  
  <p>How to fix this?</p>