bug#9132: 24.0.50; bootstrap failure on windows

[Eli Zaretskii]

> From: Sam Steingold <sds@gnu.org>
> Date: Thu, 21 Jul 2011 12:32:40 -0400
> 
> $ gmake EMACS=../bin1/emacs-2011-04-27.exe bzr-update
> ...
> Generating autoloads for calc/calc-aent.el...
> Failure in loading charset map: GB2312

This comes from charset.c, FWIW, and the reason is a failed call to
`fopen'.  It would be good to know the errno value for that failure,
and also the value of Vcharset_map_path.

Could it be that your system runs out of available file handles?  I
didn't see such problems since the old DOS days, but what else can
explain this?