Disable win32 pathnames routines on -win32 and vice versa.

Disable win32 pathnames routines on -win32 and vice versa.

#-win32 has all the win32 pathname code enabled, but it's not used
anywhere and not exported. Even if using pathnames of a different OS
may be a good idea, it's currently not presented in any usable way and
only wastes space.