bug threading [was Re: Unable to close a bug in the tracker]

[Glenn Morris]

>> One of the problems for me is that it doesn't automatically thread
>> bugs (if a reply to a bug is sent without a "in-reply-to" or
>> "references" header, as is sadly common, Debbugs could add such a
>> "references" header so all the messages are automatically threaded
>> in the MUA).

I changed it so that messages without in-reply-to or references
headers get such headers pointing to the original bug report. I hope
this is an improvement. For technical reasons, it's easier to do this
than to point to the most recent message for any given bug number. In
the absence of a real in-reply-to, there's no way to tell which is
more likely to be correct anyway.

Please file bugs against debbugs.gnu.org for things you want changing;
this was the first time I had heard the above complaint.