Updating Exim

[Pete French]

> There were changes between v3 and v4, there is a conversion tool included
> in the build but not installed which does some conversion, but it's still
> a good idea to either start from scratch or carefully check the converted
> file

I;ve just been runnign Exim 4 for the last 24 hours and it keeps exiting
with signal 11 for me (no reason determinable). I;m going to stick with 3
until it becomes a bit more stable. The 3 stuff is still there in exim-old
in the latest cvsup of ports.

-bat.