bug#6430: Emacs WINDOWS truncates exit status of processes to 8 bits

[Eli Zaretskii]

> From: Óscar Fuentes <ofv@wanadoo.es>
> Cc: npostavs@users.sourceforge.net,  macross84@ozu.es,  6430@debbugs.gnu.org
> Date: Wed, 15 Jun 2016 20:22:25 +0200
> 
> A process can return any value on the 32 bit range.

It can, but using those 2 bits for that would be silly, because doing
so will cause the exit code be interpreted as exit due to a fatal
error.