Applications were missing some features from semaphores and flags in
order to make it easier to use them as building blocks of other
synchronization mechanisms, which ABI 32 adds to address the issue. As
a result, the API evolves as follows:

- a semaphore may be broadcast using evl_flush_sem(), which is
  essentially a way to unblock all waiters atomically, returning with
  -EAGAIN to denote the condition.

- evl_broadcast_flags() sends a given bit mask to all waiters
  present. This feature makes it simpler to implement gang-based logic
  in applications, when all members from a group of threads need to be
  notified atomically using a particular bit pattern (which a
  mutex+event combo does not allow easily).

- evl_{timed_, try_}wait_some_flags() takes the set of bits to match
  in a disjunctive way (OR mode). Conversely, evl_{timed_,
  try_}wait_exact_flags() calls provide for conjunctive wait (AND
  mode). evl_{timed_, try_}wait_flags() have become wrappers to
  evl_{timed_, try_}wait_some_flags(), matching and consuming any bit
  set in the event flag group, which preserves their original
  semantics.

Signed-off-by: Philippe Gerum <rpm@xenomai.org>