[Exim] Supporting saslauthd

Hello.

Here's the first stab at supporting Cyrus SASL saslauthd daemon.

http://lxnt.info/stuff/saslauthd.diff

I've put the functions to the same files the pwcheck functions live in because
these two auth methods are actually very much alike, and both use same functions.

The request to saslauthd is of up to four parameters, all of which can
theoretically contain colons. I'd prefer to neither mix up separators with
user-supplied data nor to force users to throw ${sg everythere.

Therefore I would like something along the lines of

${if saslauthd{{<username>}{<password>}[{<servicename>}[{<realm>}]]}{1}{0}}

instead of (current)

${if saslauthd{<username>:<password>[:<servicename>[:<realm>]]}{1}{0}}

(optional items in []-s )

Philip, is this possible?

--

./lxnt