Platform Dependent Compilation
Unity includes a feature named "Platform Dependent Compilation". This consists of some preprocessor directives that let you partition your scripts to compile and execute a section of code exclusively for one of the supported
platforms.
Furthermore, you can run this code within the Editor, so you can compile the code specifically for your mobile/console and test it in the Editor!
Platform Defines
The platform defines that Unity supports for your scripts are:
| UNITY_EDITOR | Define for calling Unity Editor scripts from your game code. |
| UNITY_STANDALONE_OSX | Platform define for compiling/executing code specifically for Mac OS (This includes Universal, PPC and Intel architectures). |
| UNITY_DASHBOARD_WIDGET | Platform define when creating code for Mac OS dashboard widgets. |
| UNITY_STANDALONE_WIN | Use this when you want to compile/execute code for Windows stand alone applications. |
| UNITY_STANDALONE_LINUX | Use this when you want to compile/execute code for Linux stand alone applications. |
| UNITY_STANDALONE | Use this to compile/execute code for any standalone platform (Mac, Windows or Linux). |
| UNITY_WEBPLAYER | Platform define for web player content (this includes Windows and Mac Web player executables). |
| UNITY_WII | Platform define for compiling/executing code for the Wii console. |
| UNITY_IPHONE | Platform define for compiling/executing code for the iPhone platform. |
| UNITY_ANDROID | Platform define for the Android platform. |
| UNITY_PS3 | Platform define for running PlayStation 3 code. |
| UNITY_XBOX360 | Platform define for executing Xbox 360 code. |
| UNITY_NACL | Platform define when compiling code for Google native client (this will be set additionally to UNITY_WEBPLAYER). |
| UNITY_FLASH | Platform define when compiling code for Adobe Flash. |
| UNITY_BLACKBERRY | Platform define for a Blackberry10 device. |
| UNITY_WP8 | Platform define for Windows Phone 8. |
| UNITY_METRO | Platform define for Windows Store Apps (additionally NETFX_CORE is defined when compiling C# files against .NET Core). |
详见http://docs.unity3d.com/Documentation/Manual/PlatformDependentCompilation.html