Include errno.h; don't include fasync.h.

Include errno.h; don't include fasync.h.
(schedule): Don't return a value.
(sigcatch): Reestablish the handler first.
(getevent): Always call notify at the end.
(notify): Defer alarms around the whole body of function.

(main): Don't request SIGIO, and don't handle it.
Loop calling getevent.
(sigcatch): Delete code to handle SIGIO.
If defer_alarms is set, don't call notify, just set alarm_deferred.
(getevent): Use read, not getchar.  Handle EINTR and EAGAIN.
Set defer_alarms around realloc and schedule.
If alarm_deferred gets set, call notify.
Likewise if this event is the only pending event.
Make buf and buf_size global variables.
Don't malloc buf if it is already non-zero.
(schedule): Just exit if run out of memory.
Return the number of events.
(signal) [_CX_UX]: Add #undef.