Each type of scheduler implements its own static scheduler_t object and
returns a reference to it.
This commit also makes it a const pointer that is it can only change inside
the scheduler type subsystem but not outside for extra protection.
Signed-off-by: David Goulet <dgoulet@torproject.org>
Instead, add wrappers to do the needed action the different scheduler needs
with the libevent object.
Signed-off-by: David Goulet <dgoulet@torproject.org>
- HT_FOREACH_FN defined in an additional place because nickm did that
in an old kist prototype
- Make channel_more_to_flush mockable for future sched tests
- Add empty scheduler_{vanilla,kist}.c files and put in include.am
Signed-off-by: David Goulet <dgoulet@torproject.org>