bug#1550: 23.0.60; bad help xref or bad info installation?

[Stephen Berman]

In GNU Emacs 23.0.60.23 (i686-pc-linux-gnu, GTK+ Version 2.12.9)
 of 2008-12-12 on escher

1. emacs -Q
2. C-h f declare-function RET
3. Click or type RET on the link `elisp(Declaring Functions)' at the
   end of the *Help* buffer, to visit the Elisp info file.
==>
Emacs signals the error "byte-code: No such node or anchor:
elisp(Declaring Functions)" and the *Help* buffer switches to an *info*
buffer containing the raw text of /usr/local/info/emacs (not elisp!).
This buffer is in Info-mode but it is wholely unpropertized and the
header line is present but empty.

This is completely reproducible.  However, when I enable debug-on-error
and repeat the above steps, it does not generate a backtrace, despite
signalling the error.  (Why?  Is this a (different) bug?)  But when I
then immediately switch from the raw *info* buffer back to the *Help*
buffer again and type RET on the link, I get another error, with the
following backtrace (but only if I do not kill the *info* buffer):

txtbtG9hdeV_d.txt
Description: backtrace

I have no idea what's going on here, but it may be related to something
else I recently noticed.  My installed dir file in /usr/local/share/info
contains lots of lines like the following scattered throughout the file
(these lines are not in the dir file in the Emacs source directory):

This is ../../info/eintr, produced by makeinfo version 4.11 from 
emacs-lisp-intro.texi.

This is ../../info/sasl, produced by makeinfo version 4.11 from sasl.texi.

This is ../../info/remember, produced by makeinfo version 4.11 from 
remember.texi.

I don't know when these lines appeared, but I think it wasn't too long
ago.  Does anyone know what caused this?  FWIW, the Makefile installs
the Emacs Info files and dir in /usr/local/share/info, and I symlink
these to /usr/local/info, but I've been doing that for a long time and
I'm pretty sure the above lines are of more recent vintage.