--- ruby_2_3/thread.c  2017/04/09 11:53:53 58288
+++ ruby_2_3/thread.c  2017/04/09 13:26:01 58289
@@ -2187,6 +2187,12 @@
     return busy;
 }

+void
+rb_thread_fd_close(int fd)
+{
+    while (rb_notify_fd_close(fd));
+}
+
 /*
  *  call-seq:
  *     thr.raise