Update SDL2 to the latest commit (85bbf8e)

libs/SDL2/docs/README.md

@@ -14,7 +14,7 @@ hardware via OpenGL and Direct3D. It is used by video playback software,
 emulators, and popular games including Valve's award winning catalog
 and many Humble Bundle games.
 
-SDL officially supports Windows, Mac OS X, Linux, iOS, and Android.
+SDL officially supports Windows, macOS, Linux, iOS, and Android.
 Support for other platforms may be found in the source code.
 
 SDL is written in C, works natively with C++, and there are bindings 
@@ -34,23 +34,27 @@ More documentation and FAQs are available online at [the wiki](http://wiki.libsd
 - [DirectFB](README-directfb.md)
 - [DynAPI](README-dynapi.md)
 - [Emscripten](README-emscripten.md)
+- [GDK](README-gdk.md)
 - [Gesture](README-gesture.md)
 - [Git](README-git.md)
 - [iOS](README-ios.md)
 - [Linux](README-linux.md)
-- [OS X](README-macosx.md)
+- [macOS](README-macos.md)
 - [OS/2](README-os2.md)
 - [Native Client](README-nacl.md)
 - [Pandora](README-pandora.md)
 - [Supported Platforms](README-platforms.md)
 - [Porting information](README-porting.md)
 - [PSP](README-psp.md)
+- [PS2](README-ps2.md)
 - [Raspberry Pi](README-raspberrypi.md)
 - [Touch](README-touch.md)
+- [Versions](README-versions.md)
 - [WinCE](README-wince.md)
 - [Windows](README-windows.md)
 - [WinRT](README-winrt.md)
 - [PSVita](README-vita.md)
+- [Nokia N-Gage](README-ngage.md)
 
 If you need help with the library, or just want to discuss SDL related
 issues, you can join the [SDL Discourse](https://discourse.libsdl.org/),