It is becoming more and more common for software shops to build applications and apps for multiple platforms and devices. In addition to other applications and platforms that you need to build, you may also need to build iOS or Mac OS X applications.
It’s desirable to keep all of your source code assets in the same repository regardless of the target platforms you are building for. Developers should also work how they want to work with source control integration in their IDEs. For iOS and Mac OS X, that would most likely be Xcode with integrated git for source control.
See the entire post at http://blogs.msdn.com/b/visualstudioalm/archive/2012/10/19/building-ios-apps-in-tfs.aspx.