OpenEmbedded meta layer for darwin based SDKs

Notes: odcctools is not 64 bit safe and forces compiles to use -m32. You also need libobjc 
installed along with 32 bit libraries for ssl (libcrypto) and libuuid.
The odcctools2 version should be 64 bit safe and not need those workarounds.

You also need a OS-X sysroot tarball/zip file generated (copied) from a target OS-X
system. This is placed in the osx-runtime files directory and is used to compile the SDK
against it. It needs to contain the system libraries (/usr/lib) and include files 
(/usr/include). This tarball is not part of this meta-darwin layer and must be
created by the user. To create it, the user is required to have a legitimate Mac computer
with OSX 10.8 or later and with Xcode 5.1.0 or later installed.

To create the SDK tarball, perform the following steps using your Mac computer:

1. Install Xcode 5.1.0 or later using App Store.

2. Install the command-line development tools
    (Preferences -> Downloads -> Command-line tools)

3. Use Terminal to create the file OSX-sdk.zip from the OSX SDK (this sample assumes
   OSX 10.10):

    $ mkdir ~/Desktop/OSX-sdk
    $ cd ~/Desktop/OSX-sdk
    $ ditto `xcrun --sdk macosx10.10 --show-sdk-path` .
    $ cd ..
    $ zip -yr OSX-sdk OSX-sdk

4. Copy the created OSX-sdk.zip file to your Yocto development machine, placing it into
   meta-darwin layer:


This layer depends on:

 URI: git://git.openembedded.org/openembedded-core
 layers: meta
 branch: master

Layer Maintainer: Richard Purdie 

Please send changes to the yocto mailing list with [meta-darwin] in the subject line,
cc'ing the maintainer.