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

build.ninja

 # 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.
 
 rule gyp
   command = $
     GYP_CROSSCOMPILE=1 $
     ./third_party/gyp/gyp --depth=. -Idefault_targets.gypi $
         -Goutput_dir=out $
         --format=ninja fletch.gyp
@@ skipping 47 matching lines @@
     out/ReleaseXARM64/build.ninja: $
     gyp $
         common.gypi $
         version.gyp $
         default_targets.gypi $
         fletch.gyp $
         src/double_conversion.gyp $
         src/shared/shared.gyp $
         src/tools/driver/driver.gyp $
         src/vm/vm.gyp $
+        src/pkg/mdns/mdns.gyp $
 
 build gyp: phony$
     out/DebugIA32/build.ninja $
     out/DebugIA32Asan/build.ninja $
     out/DebugIA32Clang/build.ninja $
     out/DebugIA32ClangAsan/build.ninja $
     out/DebugX64/build.ninja $
     out/DebugX64Asan/build.ninja $
     out/DebugX64Clang/build.ninja $
     out/DebugX64ClangAsan/build.ninja $
@@ skipping 40 matching lines @@
         src/double_conversion.gyp $
         src/shared/shared.gyp $
         src/tools/driver/driver.gyp $
         src/vm/vm.gyp $
 
 build mbed: phony$
     out/DebugMBED/build.ninja $
     out/ReleaseMBED/build.ninja $
 
 default gyp