To pick up this sort of bug, perhaps "make install" should attempt to remove config.h if it exists in the target include directory?

I don't think so. Once Python 2.2 is released, it will install its headers into <prefix>/include/python2.2, which will be empty since it is the first usage ever of this directory; the previous *release* installed its files into a different location. Giving the advice to people to remove their <prefix>/include/python2.2, and (most of) <prefix>/lib/python2.2 if they update from an earlier alpha release might be a good idea, though: there might be other removed or renamed files whose absence they would not notice. Regards, Martin