tools: fix gyp to work on MacOSX without XCode
tools: fix gyp to work on MacOSX without XCode

This issue has already submitted to the upstream in
https://code.google.com/p/gyp/issues/detail?id=477
Use this commit until the upstream is to be fixed.

PR-URL: https://github.com/iojs/io.js/pull/1325
Reviewed-By: Fedor Indutny <e39d94bae70283f13d24c278e04952d6dad9384b@indutny.com>
Reviewed-By: Ben Noordhuis <59bd0a3ff43b32849b319e645d4798d8a5d1e889@bnoordhuis.nl>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node