astropy/astropy — pull request #316 by mdboom (2012-07-11 17:13:46+00:00)
Title: Add a `--use-system-expat` option to use the system's expat library.

This makes is easier for packagers to specify that they want to use the system's expat library.

It also lays the groundwork for doing this more generally, namely:

1) Easily adding build arguments from a packages `setup_package.py`

2) Making pkg-config calls, if necessary and available, to get the compiler arguments to link to a particular library.

@iguananaut may want to look at this since `io.fits` also has some external packages that may need similar functionality.