平时写代码经常会区分平台。然而又不记得，故特做此笔记。。

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_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.
Also you can compile code selectively depending on the version of the engine you are working on. Currently the supported ones are:

UNITY_2_6 Platform define for the major version of Unity 2.6.
UNITY_2_6_1 Platform define for specific version 1 from the major release 2.6.
UNITY_3_0 Platform define for the major version of Unity 3.0.
UNITY_3_0_0 Platform define for the specific version 0 of Unity 3.0.
UNITY_3_1 Platform define for major version of Unity 3.1.
UNITY_3_2 Platform define for major version of Unity 3.2.
UNITY_3_3 Platform define for major version of Unity 3.3.
UNITY_3_4 Platform define for major version of Unity 3.4.
UNITY_3_5 Platform define for major version of Unity 3.5.
UNITY_4_0 Platform define for major version of Unity 4.0.
下面的以此类推。。。。