bug#17622: 24.4.50; bootstrap failure

[Eli Zaretskii]

> Date: Thu, 29 May 2014 08:38:24 -0400
> From: Ken Brown <kbrown@cornell.edu>
> CC: Eli Zaretskii <eliz@gnu.org>,
>         Fabrice Popineau <fabrice.popineau@gmail.com>
> 
> On 5/29/2014 12:56 AM, Katsumi Yamaoka wrote:
> > I verified simply reverting r117168 builds Emacs successfully on
> > Cygwin.
> 
> The removal of mmap_set_vars is what caused the problem.  The following 
> patch fixes restores mmap_set_vars and fixes the problem.  Eli and 
> Fabrice, is the w32 build still OK with this patch?

Yes, but there's no need to return all this cruft, as most of it is
not needed.  We only need to reset mmap_regions and mmap_fd.

I installed a patch just now that should fix the crashes, please take
a look.  (It also removes two unused variables, and fixes the
initialization of buffer text in init_buffer, which was slightly
wrong.)