riscospath.extsep, and use os.extsep throughout.

into the relevant path modules.  See patch #686397.

Dietmar Schwertberger.
Bugfix candidate.
"""
RISCOS/Modules/getpath_riscos.c:
Include trailing '\0' when using strncpy [copy
strlen(...)+1 characters].

Lib/plat-riscos/riscospath.py:
Use riscosmodule.expand for os.path.abspath.
[fixes problems with site.py where
abspath("<Python$Dir>") returned
join(os.getcwd(), "<Python$Dir>") as e.g.
"SCSI::SCSI4.$.<Python$Dir>" because "<Python$Dir>"
wasn't recognised as an absolute path.]
"""

We have 5 implementations of walk(), and 5 different docstrings.  Combined
'em.  Let's see how long it takes before they're all different again!

   Once upon a time, I put together a little function
   that tries to find the canonical filename for a given
   pathname on POSIX. I've finally gotten around to
   turning it into a proper patch with documentation.
   On non-POSIX, I made it an alias for 'abspath', as
   that's the behavior on POSIX when no symlinks are
   encountered in the path.

   Example:
   >>> os.path.realpath('/usr/bin/X11/X')
   '/usr/X11R6/bin/X'