modularize callerid

[kaniini]

This MR is the second part of refactoring the message forwarding path in the IRCd. We also add a relaxed caller id mode which works similarly to Hybrid's soft callerid as usermode +G.

[kaniini]

@aaronmdjones what is the current blockers on this? i have validated that the module works fine in a complex network topology.

[aaronmdjones]

@kaniini I have not yet had the time to testnet it. Should be done by tomorrow evening.

[aaronmdjones]

@kaniini This appears to break the behaviour of automatically adding PRIVMSG targets to your /ACCEPT list.

17:42 <Aaron1> Hi
17:42 <Aaron3> Hi
17:42 -!- [chary1.testnet] Aaron1 is in +g mode (server-side ignore.)
17:42 -!- [chary1.testnet] Aaron1 has been informed that you messaged them.

[kaniini]

This was resolved by changing the scope of the privmsg_user hook. I verified that all hook subscribers are safe with this change.

[aaronmdjones]

Okay, it does indeed all work now.

My only remaining concerns are:

1) This user mode +G behaves differently from the user mode +G in hybrid, which this idea comes from. In hybrid, it's a self-contained mode, and can be set and unset independently of +g, rather than modifying its behaviour. Making this behave like that would be a relatively minor adjustment to your if statements, and I believe is a worthwhile change.

Something to bear in mind though is that the source will need to receive a different error text (mentioning user mode `+G` instead of `+g`) if the message is not allowed, and the umode help file will need to be updated again.

EDIT: Also, it should check for `+g` first.

2) The change to the privmsg_user hook is indeed safe, but now extensions/umode_noctcp.c needs this in umode_noctcp_process, or it will be pointlessly checking for the user mode +C twice:

        if (! MyClient(data->target_p))
                return;