kqueue: ignore ENOENT error

File descriptor might be closed during callback, all events that was reported
before the callback are not valid and trying to remove them will result
in ENOENT. This error can be safely ignored.

src/unix/kqueue.c

@@ -197,7 +197,9 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
           /* TODO batch up */
           struct kevent events[1];
           EV_SET(events + 0, fd, ev->filter, EV_DELETE, 0, 0, 0);
-          if (kevent(loop->backend_fd, events, 1, NULL, 0, NULL)) abort();
+          if (kevent(loop->backend_fd, events, 1, NULL, 0, NULL))
+            if (errno != ENOENT)
+              abort();
         }
       }
 
@@ -208,7 +210,9 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
           /* TODO batch up */
           struct kevent events[1];
           EV_SET(events + 0, fd, ev->filter, EV_DELETE, 0, 0, 0);
-          if (kevent(loop->backend_fd, events, 1, NULL, 0, NULL)) abort();
+          if (kevent(loop->backend_fd, events, 1, NULL, 0, NULL))
+            if (errno != ENOENT)
+              abort();
         }
       }