Message 277403 - Python tracker

I don't have any philosophical opposition to using pkg-config, but it would be nice to avoid making configure/Makefile/setup.py any more complex than they already are.  If you can somehow simplify those files (without breaking anything) by using pkg-config, I'd be all for it :)

Resetting the version to 3.7, this feels like a pretty big change.  If it turns out well, we can consider backporting it later.