uev_timer_set(): Check return value of timerfd API

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

timer.c

@@ -131,7 +131,8 @@ int uev_timer_set(uev_t *w, int timeout, int period)
 
 		msec2tspec(timeout, &time.it_value);
 		msec2tspec(period, &time.it_interval);
-		timerfd_settime(w->fd, 0, &time, NULL);
+		if (timerfd_settime(w->fd, 0, &time, NULL) < 0)
+			return 1;
 	}
 
 	return uev_watcher_start(w);