BBDB et al. prevent Emacs from being installed

[Daniel Brockman <daniel@brockman.se>]

I have noticed that certain Debian packages that install files into
`/etc/emacs/site-start.d/' prevent Emacs from being installed.
One such package is `bbdb'; two others are `dictionaries-common' and
`dictionary-el'.

To see the problem in action, first make sure you have BBDB installed.
(As I said, `dictionaries-common' and `dictionary-el' work too.)

    apt-get install bbdb

Now install an Emacs package --- either install a different flavor or
reinstall one you already have.

    apt-get --reinstall install emacs21

BANG.

To get your Emacs back, remove BBDB and then install Emacs.
Then install BBDB again if you want it.

I'm guessing there are other packages that cause similar problems.
However, the rest of the Emacs application packages that I have
installed (27 in total) do play nice.

As for what the hell is going on, the reason you can't install Emacs
while BBDB is installed is that BBDB depends on having certain
byte-compiled files installed in `/etc/emacs${flavor}/site-lisp/'.
Naturally, these files can only be created by `emacs${flavor}'.
The catch is that `emacs${flavor}' cannot normally run if some file in
`/etc/emacs/site-start.d/' is raising errors --- for example, by
attempting to load a file that does not exist.

Unless someone gives me a reason not to, I will file bugs to the
problematic packages.  I'm not sure how to fix this problem, but I do
think it should be fixed.

    Note for people using emacs-snapshot:

    As this problem only surfaces when installing a new Emacs flavor,
    you are likely to experience it for the first time when installing
    emacs-snapshot.  However, as is evident from the fact that it can
    be reproduced without having emacs-snapshot in the picture, we
    can't blame Jerome. :-)

-- 
Daniel Brockman <daniel@brockman.se>