The `watch-check` function now has a new argument which can be used to pass data to watch_notify callbacks.
New `watch_add` and `watch_del` hooks are called whenever new entries are created or removed.
New `monitor_notification` hook is called whenever a RPL_MONONLINE or RPL_MONOFFLINE is being sent, so a module can add its own notification besides it.
It often takes a while for the actual crash to occur but eventually an
attempt would be made to access inaccessible memory of the previously
freed .so module.
Reported by and traced with the help of both Wick and Krstarica.
This will likely reduce performance, but this should not matter in modern times.
Also added flags to let modules know which one the entry belongs to, and what
to do with it.
Now modules should be able to add their own WATCH methods (like IRCv3 MONITOR),
or extend functionality to notify about other changes than the default log on,
log off and away statuses (like SETNAMEs).