bug#14513: 24.3.50; Site load-path pieces differ in MSYS build

[Eli Zaretskii]

> From: Achim Gratz <Stromeko@nexgo.de>
> Date: Thu, 30 May 2013 21:57:02 +0200
> 
> Eli Zaretskii writes:
> >> FWIW, I use a directory structure which relies on a ../site-lisp to be
> >> accessible by multiple Emacs versions installed in parallel, just like
> >> on UN*Xy boxes.
> >
> > Unix boxes use exactly the directory structure that is now encoded in
> > epaths.h.  So we got closer to Unix, not farther.
> 
> On UN*X the installation of several versions is usually done into the
> same $prefix, but you don't normally do that on Windows where each
> install is usually unpacked into its own tree.

It was, until now.  From now on, they will all easily unpack into the
same tree, because the top-level directory in the zip file won't be
emacs-XX.YY anymore.

> This means that when it's time to remove an old version tree you'd
> need to remember that site-lisp must be rescued or you need to start
> installing your Windows Emacsen into the same $prefix just like on
> UN*X.  Which is a bit annoying when you want to keep some versions
> around from before that change or your system administrator can't be
> convinced to change how the installation is done.

Well, then just don't do that.  Don't unpack each version into a
separate directory.  That's what this change was all about.