Auto-load safe-path and auto-load scripts-directory on Windows

[Eli Zaretskii]

> Date: Sat, 29 Aug 2015 11:55:34 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> 
> I've noticed that the default values of these 2 path lists use ':' as
> directory separator, even on MS-Windows.

Also, trying to fix that by configuring with, e.g.

   --with-auto-load-dir='$debugdir;$datadir/auto-load'

doesn't work, as the resulting binary only shows $debugdir in the
value.  Evidently, the semi-colon and everything after it was
stripped, even though it was in '..' quotes.  How can I provide a
Windows-style path with this configure-time option?

TIA