mention sdl as platform

CMake-Build-Options.md

@@ -7,7 +7,7 @@ You must define `-DCUSTOMIZE_BUILD=ON` in order for many of these options to app
 | **Option**                        | **Description**                                           | Possible Values (first is default)|
 |:-----------------------------:|:-----------------------------------------------------:|:------------:|
 |`USE_EXTERNAL_GLFW`            | Link raylib against system GLFW instead of embedded one | **`OFF`** `ON` `IF_POSSIBLE`|
-|`PLATFORM`                     | Platform to build for. | **`Desktop`** `Web` `Android` `Raspberry Pi`|
+|`PLATFORM`                     | Platform to build for. | **`Desktop`** `Web` `Android` `Raspberry Pi` `SDL`|
 |`OPENGL_VERSION`               | Force a specific OpenGL Version? | **`OFF`** `4.3` `3.3` `2.1` `1.1` `ES 2.0` `ES 3.0`|
 |`BUILD_EXAMPLES`               | Build examples | **`OFF`** `ON` |