Skip invalid file descriptor test on Mac

Author: morrisonlevi

ext/standard/tests/file/php_fd_wrapper_04.phpt

@@ -1,5 +1,10 @@
 --TEST--
 php://fd wrapper: invalid file descriptor
+--SKIPIF--
+<?php
+// At least on Mac 10.14 Mojave; not sure about older versions
+if (strtolower(PHP_OS) == 'darwin') die('skip: the warning output is different on MacOS');
+?>
 --FILE--
 <?php
 fopen("php://fd/1023", "w");