mod_posix: Move everything to util.startup
This allows greater control over the order of events.
Notably, the internal ordering between daemonization, initialization of
libunbound and setup of signal handling is sensitive.
libunbound starts a separate thread for processing DNS requests.
If this thread is started before signal handling has been set up, it
will not inherit the signal handlers and instead behave as it would have
before signal handlers were set up, i.e. cause the whole process to
immediately exit.
libunbound is usually initialized on the first DNS request, usually
triggered by an outgoing s2s connection attempt.
If daemonization happens before signals have been set up, signals may
not be processed at all.
Welcome hackers!
This project accepts and *encourages* contributions. If you would like to get
involved you can join us on our mailing list and discussion rooms. More
information on these at https://prosody.im/discuss
Patches are welcome, though before sending we would appreciate if you read
docs/coding_style.md for guidelines on how to format your code, and other tips.
Documentation for developers can be found at https://prosody.im/doc/developers
Have fun :)