bug#7942: 23.2; Duplicate entries in Info dir file

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 30 Jan 2011 15:37:19 +0100
> From: Ulrich Mueller <ulm@gentoo.org>
> Cc: emacs@gentoo.org
> 
> If Emacs is the first or only package that installs its Info files
> into an otherwise empty directory (e.g., in Gentoo Emacs is configured
> with --infodir=/usr/share/info/emacs-23 to allow for multiple Emacs
> versions), then all entries in the resulting dir file will occur
> twice.
> 
> The bad Info dir file installed by Emacs 23.2 is attached.
> 
> The cause appears to be that the Makefile first copies the pre-made
> dir file, but then also calls install-info for each Info file.

That's not the reason, because install-info is supposed to replace the
old entries with the new ones (unless there's a bug in install-info).

I think the reason is that the section names used by the distributed
info/dir file are different from the section names stated by the
individual Info files.  Could you perhaps verify that?

> Attached patch fixes the problem for me. I suggest that this should be
> applied to the emacs-23 branch.

Thanks.

However, isn't it better to invoke install-info with the --keep-old
option?  Does that solve the problem?