Adds two new callbacks: "prepare" watchers, which fire immediately
before we poll for I/O, and "check" watchers, which fire immediately
after we finish polling and before we process events. This allows other
event loops to be embedded into libevent's, and enables certain
performance monitoring.
Closes: #710
Due to regress linked with event and event_core (both of them includes
evthread.c) there will be two different evthread_id_fn_ variables under
mingw64:
evthread_id_fn_: &0x5294f20a8
evthread_id_fn_: &0x4ba0030a8
And because of this evthread_use_pthreads() can/will set one copy of
variables while evthread*() functions will access another, which will
break a lot of things (for example main/del_notify test).
Fixes: #792
Before this patch we have one test.sh (well test-script.sh), and tooks
very long to run it sequentially, but they are pretty lightweight, so we
should run then in parallel.
Currently an out-of-tree build will either write to the src dir or reuse
the existing regress.gen.[c,h]. But if building from a read-only git
tree (or if the git dir is cleaned), these files will not exist and the
build fails. So write the files to the build dir. If the system does
not have python, the regress.gen.[c,h] will be used from the src dir if
they exist.