Update SDL to version 2.0.10.

libs/SDL2/test/testcustomcursor.c

@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+  Copyright (C) 1997-2019 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
@@ -203,7 +203,7 @@ main(int argc, char *argv[])
             break;
         }
         if (consumed < 0) {
-            SDL_Log("Usage: %s %s\n", argv[0], SDLTest_CommonUsage(state));
+            SDLTest_CommonLogUsage(state, argv[0], NULL);
             quit(1);
         }
         i += consumed;