Update SDL to version 2.0.10.

libs/SDL2/test/testviewport.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
@@ -161,8 +161,8 @@ main(int argc, char *argv[])
             }
         }
         if (consumed < 0) {
-            SDL_Log("Usage: %s %s [--target]\n",
-                    argv[0], SDLTest_CommonUsage(state));
+            static const char *options[] = { "[--target]", NULL };
+            SDLTest_CommonLogUsage(state, argv[0], options);
             quit(1);
         }
         i += consumed;