mxcl/homebrew — pull request #11407 by 2bits (2012-04-03 03:40:27+00:00)
Title: mapnik: fix compile error with system Python

Mapnik by default tries to install to the site-packages in /System
when brewed against system Python. This causes a build error
because that directory is not writeable. Mapnik correctly
determines the versioned site-packages name without modification,
but for Homebrew it needs the proper prefix.

* Add the standard `which_python` function to the formula.
* Add a scons argument for `PYTHON_PREFIX=/usr/local`
* Add the standard caveat for `PYTHONPATH`.

Discussed upstream: https://github.com/mapnik/mapnik/issues/1155
and tested on Lion against the system Python.

Fixes #11389