There used to be an Xcode project that lived here. However, it is no longer.
Please use CMake to generate an Xcode project.
Any Mac OS X SDK that is 10.6 or higher will work. However, the 10.6 SDK is needed to offer full screen support at this time.
Please see this comment on how to install 10.6 SDK in Xcode if this feature is necessary for your setup.
Please note that you must restart Xcode after installing the SDK, in case Xcode is running, for it to detect the new SDKs.