Revert "Extend the mDNS package with a native extension used on Mac OS"

src/pkg/mdns/mdns_extension_linux.cc

Index: src/pkg/mdns/mdns_extension_linux.cc
diff --git a/src/pkg/mdns/mdns_extension_linux.cc b/src/pkg/mdns/mdns_extension_linux.cc
deleted file mode 100644
index 9ab4d2b48b4d742387af38d7c5f308c5b31d1bf5..0000000000000000000000000000000000000000
--- a/src/pkg/mdns/mdns_extension_linux.cc
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright (c) 2015, the Fletch project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE.md file.
-
-#if defined(FLETCH_TARGET_OS_LINUX)
-
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "include/dart_api.h"
-#include "include/dart_native_api.h"
-
-#include "mdns_extension.h"
-
-// Dummy implementation for Linux.
-void HandleLookup(Dart_Port port_id, char* adress) {}
-
-#endif