Oh you meant while running Mercurial? I was pretty confused as to why we need to
scan ~/lib/python while running make uninstall. But what you propose again
becomes too one-sided. What if a user had done make install-home before and now
running make install? This method breaks.

A better approach I feel is to supersede the path of install over the previous
install path in your sys.path after each install, but that again depends on how
to do it for individual users. (Only way I can think as of now is to again set
PYTHONPATH :P )