[sork] Patch for vacation forwards-driver (.forward-parser)

[Espen Jürgensen]

> It must at least be able to handle any thing these modules generate, and
> to recognize and have a resolution for those that are not in that format.
> This includes things like End of Line characters (or lack thereof),
handling
> backquotes properly, etc.

EOLs shouldn't be problem, but I don't know about backquotes. Will test it
later. It uses imap_rfc822_parse_adrlist(), and I don't know how it reacts
to backquotes.

Anyway, whether it works with backquotes or not, the parser is still an
improvement. The current version of vacation simply overwrites .forward no
matter what it contains, and even without warning.

> I really hate discarding user data.  So I'm not happy with #1.  Maybe
> a modified #1 that doesn't take any action if unknown data is found
> would be better?

Yes, I agree that discarding user data isn't so good, but on the other hand,
you don't want to simply forbid the user from making any changes. That would
be quite frustrating.

Regards,
Espen