bug#24656: 25.1; Emacs leaves lock files on a CIFS share

[Eli Zaretskii]

> From: Achim Gratz <Stromeko@nexgo.de>
> Date: Tue, 11 Oct 2016 19:43:08 +0200
> 
> You could maybe copy what Cygwin does if you need to handle wierdd characters 
> in
> file names:
> https://cygwin.com/cygwin-ug-net/using-specialnames.html#pathnames-specialchars

Thanks.

That's what Samba seems to do, and that's the cause of this bug in the
first place.

We don't have the reason Cygwin does to deal with such problem, we can
simply use another character.  It's simpler and doesn't assume
anything about PUA codepoints or their support in the underlying
filesystem.