In processPendingNotification() in signals.c, we go around a loop processing
queued-up notifications. We should reschedule if any of the processed notifications
would have caused a reschedule. However, the code in the loop was using

    need_to_reschedule = queueSignal(monH, &mon->monitor_waitq);

where it meant to use |=, so only the last notification could cause a reschedule.

Thanks to John Seamons for noticing this.