When we don't have the thread id yet, don't add the pollfds yet
but wait until we do our first wait operation.
Use flags for eventfd. We can use this to communicate between all kinds
of threads with read/write.
Use evl_init() in the init function, don't attach the main loop, just
the thread that dos the first poll.
This is more in line with wayland and it allows us to create new
interfaces in modules without having to add anything to the type
enum. It also removes some lookups to map type_id to readable
name in debug.
Add system functions that can execute on the evenless Real-Time
subsystem. https://evlproject.org/
Enable this plugin as the system library for the data thread and
all poll/timerfd/eventfd will execute on the evl subsystem.
