doc(wiki): Updated "binding.gyp" files out in the wild (markdown)

"binding.gyp"-files-out-in-the-wild.md

@@ -5,7 +5,7 @@ To add to this page, just add the link to the project's `binding.gyp` file below
  * [libxmljs](https://github.com/polotek/libxmljs/blob/master/binding.gyp)
  * [node-buffertools](https://github.com/bnoordhuis/node-buffertools/blob/master/binding.gyp)
  * [node-canvas](https://github.com/LearnBoost/node-canvas/blob/master/binding.gyp)
- * [node-ffi](https://github.com/rbranson/node-ffi/blob/master/binding.gyp)
+ * [node-ffi](https://github.com/rbranson/node-ffi/blob/master/binding.gyp) + [libffi](https://github.com/rbranson/node-ffi/blob/master/deps/libffi/libffi.gyp)
  * [node-time](https://github.com/TooTallNate/node-time/blob/master/binding.gyp)
  * [node-serialport](https://github.com/voodootikigod/node-serialport/blob/master/binding.gyp)
  * [node-weak](https://github.com/TooTallNate/node-weak/blob/master/binding.gyp)