bug#13125: Fix permissions bugs with setgid directories etc.

[Michael Albinus]

Paul Eggert <eggert@cs.ucla.edu> writes:

> I'm attaching a patch, which changes file-attributes so that it now
> outputs a placeholder value instead of the old 9th attribute member,
> since the value is rarely needed and almost nobody seems to be using
> it or caring that it's wrong.  Instead, the patch moves this
> functionality to file-ownership-preserved-p via a new argument GROUP.
> The patch also adds new functions group-gid and group-real-gid for use
> with the backup-file heuristic.
>
> This patch is relative to trunk bzr 111160.

You have also patched tramp-sh.el, thanks. However, Tramp has its own
life outside Emacs, the change must be backwards compatible for older
Emacs versions as well as for XEmacs.

Best regards, Michael.