Fix Python – Differences between distribute, distutils, setuptools and distutils2?

The Situation
I’m trying to port an open-source library to Python 3. (SymPy, if anyone is wondering.)
So, I need to run 2to3 automatically when building for Python 3. To do that, I need to use distribute. Therefore, I need to port the current system, which (according to the doctest) is distutils.

The Problem
Unfortunately, I’m not sure what’s ….