Re: A few Windows build fixes

[Eli Zaretskii]

> From: Andy Moreton <address@hidden>
> Date: Fri, 02 Sep 2011 01:14:02 +0100
> 
> > (convert-standard-filename
> >  "/cygdrive/c/programs/emacs-24.0.50/lisp/w32-fns.el")
> >
> > ; => "c:\\programs\\emacs-24.0.50\\lisp\\w32-fns.el"
> >
> > does the right thing.
> 
> This is buggy. The '/cygdrive' prefix can be replaced per-user or system
> wide - see the cygwin mount(1) manpage for details.

Full support for Cygwin-specific file names can only happen on the C
level.  E.g., in w32.c:normalize_filename.  We should probably have a
similar function in ntlib, because lib-src programs will need to use
it as well (see the example with emacsclient posted here).

Anything else will necessarily be buggy or at least incomplete.

And even on the C level, this should be a user option, because
otherwise users who don't have Cygwin anywhere in sight will be unable
to have a real `x:/cygdrive' directory on each of their logical disks.