[Python-3000] Removing windows 95 specific code

["Martin v. Löwis"]

> Python 3.0 has already dropped support for Windows 9x in several
> places, and is now expected to only work with the NT family.
> 
> I propose to remove the remaining code specific to windows 9x/ME.
> 
> This includes:
> - Py_WIN_WIDE_FILENAMES is always defined
> - when given a unicode string, try to always use the wide version of
> the win32 api.
> - w9xpopen will disappear
> 
> Are there objections?

Not in principle. However:
a) changes that apply to 2.6 as well should be done there *first*, and
   then merged to 3.x (although there are few of them), and
b) there is debate whether w9xpopen can disappear on NT (Tim Peters once
   hinted that it should stay if COMSPEC is not cmd.exe).

> on posix platforms, os.path.supports_unicode_filenames is False.
> So far, this variable is only used to run test_pep277.py or not. Did
> we make some progress on this topic since the unicode-everywhere
> rewrite? (see also http://bugs.python.org/issue767645 )

No, and I don't think there can be any progress. POSIX will never ever
support arbitrary Unicode file names, in arbitrary locales.
(of course, no system supports *all* possible Unicode strings as file
names, but some have only a tiny list of characters being excluded, plus
constraints on the maximum length of a file name).

Regards,
Martin