Updated SDL 2.0.16 headers and Mac version of libraries to fix GitHub actions

code/SDL2/include/SDL_test_random.h

@@ -1,6 +1,6 @@
 /*
   Simple DirectMedia Layer
-  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
 
   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
@@ -98,7 +98,7 @@ extern "C" {
  *
  *  \param rndContext     pointer to context structure
  *
- *  \returns a random number (32bit unsigned integer)
+ *  \returns A random number (32bit unsigned integer)
  *
  */
  unsigned int SDLTest_Random(SDLTest_RandomContext *rndContext);