Re: A few Windows build fixes

[Stefan Monnier]

> Going through w32-fns.el, I see there's `w32-convert-standard-filename'
> which actually replaces /cygdrive/ paths correctly.  Indeed, 

Well, that's a bug: convert-standard-filename was meant for something
completely different and has degenerated into an ugly beast whose
behavior is a big mess, so we need a new function instead which is
clearly documented as translating a file-name "valid in the system,
outside of Emacs" into a filename "valid within Emacs".  And it needs to
be hookable so that users can add things like "proper/careful handling
of cygwin file names", as opposed to merely handling "/cygdrive/...".


        Stefan