Not buildling under Xcode 5.1 DP1 (Garbage collection issue)

Garbage collection is no longer supported on XCode 5.1 so I'm getting compiler errors when trying to build.

```
//:configuration = Debug
GCC_ENABLE_OBJC_GC = supported

//:configuration = Release
GCC_ENABLE_OBJC_GC = supported

//:completeSettings = some
GCC_ENABLE_OBJC_GC
```

**_This is the error**_

```
    error: garbage collection is no longer supported
```
