Include a backport of the sysconfig module

[embray]

At a certain point I wanted to avoid doing this, but I don't really see the problem is when I think about it. Including a backport of the sysconfig module would enable support for resources.

That said, the more distutils2 features that get implemented, the more I need to consider just forking distutils2 and rewriting d2to1 as a bootstrap for a stable-ish version of distutils2.