Installing qt on 10.7

Worked following these instructions: http://www.noktec.be/python/how-to-install-pyqt4-on-osx with important exceptions.

1. I installed sip and pyqt against my virtualenv, not against the system python
2. I had to get g++-4.2 to precede g++-4.6 on my path, which was hard.

This command:
PATH=/usr/bin:$PATH CC=g++-4.2 CXX=g++-4.2 ~/virtual-python/bin/python configure.py -d ~/virtual-python/lib/python2.7/site-packages/ --verbose

worked, whereas this one:

CC=g++-4.2 CXX=g++-4.2 ~/virtual-python/bin/python configure.py -d ~/virtual-python/lib/python2.7/site-packages/ --verbose

did not.

Similarly, needed same prefixes when doing make.