mgenmid: add option -d for custom domain

[ghost]

In my setup, I use mblaze across multiple mailboxes, each with different addresses and domains, which they provide through mailbox-local configuration files. I needed this option in order to select the domain programmatically.

[leahneukirchen]

If you use multiple mblaze profiles, you can set fqdn: there.

[ghost]

Yes, but that means I need a .mblaze directory which contains the profile for every local mailbox like this; it's wasteful, and I essentially end up writing a wrapper script for mgenmid which deals with it properly.

Regardless, I'm using this patch locally; I've provided it here for the sake of doing so, and if it doesn't seem useful, feel free to close it.

[leahneukirchen]

I think it would make more sense to use, say, an environment variable $MBLAZE_FQDN if it is set. Then you can set it before calling mcom etc.

[ghost]

But such a design will lead to environment variables for every profile setting. I don't think that's a good idea either.

[Anachron]

I think this can be closed, no? @leahneukirchen