rem: state = disable_interrupts();
add: ASSERT(B_ONE_SHOT_RELATIVE_ALARM == B_ONE_SHOT_RELATIVE_TIMER);
context: set_alarm(bigtime_t time, uint32 mode){	struct thread *t = thread_get_current_thread();	int state;	bigtime_t rv = 0;	state = disable_interrupts(); //XXX really here? and what about a spinlock?	if (t->alarm.period)		rv = (bigtime_t)t->alarm.entry.key - system_time();	cancel_timer(&t->alarm);	if (time != B_INFINITE_TIMEOUT)		add_timer(&t->alarm, &alarm_event, time, mode);	restore_interrupts(state);	return rv;}