Unity预定义标签的种类还有很多,不仅可以区分平台还可以区分版本。
Note: These defines were introduced at version 3.0.
Also you can compile code selectively depending on the version of the engine you are working on. Currently the supported ones are:
详细内容可以查看官网http://docs.unity3d.com/Documentation/Manual/PlatformDependentCompilation.html