MIME, or subverting quoted-unprintable

I'd like Exim to be able to Do Something about the awfulness that is
quoted-printable.

I don't know whether Phil might have time to implement what I'm about
to propose, but I'd like to suggest it for consideration:

The problem: the MIME RFCs specify that 8-bit messages must be mangled
using quoted-printable if the receiving MTA doesn't support EHLO and
advertise 8BITMIME. This is in direct opposition to what everyone was
doing previously (just-send-8) and causes problems with eg patchfiles
and non-MIME MUAs.

I'd like Exim to be able optionally to:

* Decode incoming quoted-printable into 8bit. This should definitely
be on by default.

* Decode incoming base64'd text/* types into 7bit/8bit. This should
probably be off by default.

* Send the 8BITMIME response to EHLO. This should be settable
independently of the settings of the other MIME-related options, and
should be on by default.

* When trying to deliver an 8bit message to a non-8BITMIME MTA, encode
into quoted-printable. (I might not use this option, but the MIME
fanatics will jump down your throat saying you have `half-baked MIME
support' if it's not there.)

* When trying to deliver an 8bit message to a non-8BITMIME MTA, send
the message as 8bit anyway.

These options should be settable on a per-remote-MTA basis. What you
do by default with outgoing 8bit mail to a non-8BITMIME MTA is a
religious matter. I think you should just-send-8.

This would allow things like:

* A mailing list server that undoes MIME braindamage before doing
just-send-8 on outgoing digests and messages.

* A gateway system that undoes MIME braindamage before passing the
message using just-send-8 to 8 bit clean MTAs inside the organisation.

* Users with non-MIME MUAs on the system running Exim do not have to
see MIME braindamage.

* MIME freaks can configure Exim to behave as specified by the RFCs
when talking to the outside world, and still run it as a gateway to
non-MIME mailers inside the organisation.

Ian.