Without-interruption will replace without-interrupts wherever
exclusivity is not thought to be needed -- just uninterruptibility.
Without-interrupts is deprecated because it is broken in multi-
processing worlds where it cannot provide exclusive access to the heap
as it does in uniprocessing worlds.
with-thread-mutex-try-lock
with-thread-mutex-unlocked
with-thread-timer-stopped
+ (without-interruption with-thread-events-blocked)
without-thread-mutex-lock
yield-current-thread)
(export (runtime interrupt-handler)