This is needed by the tunnel module rewrite, which runs pa_mainloop in
the IO thread instead of pa_rtpoll.
Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
This adds pa_assert_io_context() and pa_assert_ctl_context() in addition
to a few related macros. When called they will fail when the current execution
context is not IO resp. not control context. (aka 'thread' context vs.
'main' context)
