From: Fred L. Drake, Jr. [mailto:firstname.lastname@example.org]
There's one aspect that doesn't appear to have been addressed for Unix: there are two reasonable values for extinstallpath. In multi-architecture installations, where the Python portions of the library are shared among architectures, there are two site-packages directories:
I agree entirely. I have no knowledge of the issues on Unix, and hence I can make no comment.
As far as I am concerned, I feel very strongly that this should go in for Windows (where I believe that the current use of a "bare" sys.prefix is wrong), but I have no view at all on other platforms. My PEP was originally entitled "Using site-packages on Windows" - I am happy if the scope gets extended, but don't rely on me to do it - and please don't let the key point (for me) which is fixing Windows, get sidetracked by issues for Unix, where (as far as I know) the current status quo is perfectly acceptable to the majority of users.
So I'd vote to leave sys.extinstallpath undefined except on Windows, and leave the other platforms for a new PEP.