RFC-2047 vs. INN Compatibility Issue

[Matthias Andree <matthias.andree@gmx.de>]

Hi,

Gnus just generated an article that news.cis.dfn.de aka news.fu-berlin.de
didn't accept (they run some INN version I can't figure out via NNTP as they
put me into NNRPD directly rather than INND). Their server complained 441
437 Missing "Subject" header.

What happened? Gnus generated a header like this in a reply:

Newsgroups: de.comm.software.mailserver
Followup-To: poster
Subject: 
 =?iso-8859-15?q?Re:_kein_Anmeldung_mit_pop3_m=F6glich_bei_courier-imap?=

Looks like this is fine according to RFC-2822 and 2047, but it is not a
recommended way to encode the header, rfc2047.el encodes too much currently.

Anything before the first word that needs encoding and anything after the
last word that needs encoding should be left unencoded, at least and
particularly the Re: should never be part of an encoded string. Rationale:
non-MIME-Aware readers will duplicate the Re: if it's encoded like this.

I'd suggest that the header be written as (I don't care about the
indentation here):

Subject:·Re:
 =?iso-8859-15?q?_kein_Anmeldung_mit_pop3_m=F6glich_bei_courier-imap?=

or even better:

Subject: Re: kein Anmeldung mit pop3 =?iso-8859-15?q?m=F6glich?=
 bei courier-imap

Care must be taken not to encode each word individually because that's
inefficient, and because adjacent encoded-words get their separating LWS
_removed_, so =?iso-8859-1?q?test?= =?iso-8859-1?q?word?= becomes
"testword", not "test word".

Can anyone help with a rfc2047.el patch?

Thanks in advance,
Matthias