Fix data-loss with --version.

Fix data-loss with --version.

* emacs.c (close_output_streams): Use strerror, not emacs_strerror,
as we can't assume that emacs_strerror is initialized, and strerror
is good enough here.
(main): Invoke atexit earlier, to catch earlier instances of
sending data to stdout and exiting, e.g., "emacs --version >/dev/full".