Added comment about SDL and SDL_INIT_GAMECONTROLLER. (#2809)

examples/example_sdl_opengl3/main.cpp

@@ -27,6 +27,8 @@
 int main(int, char**)
 {
     // Setup SDL
+    // (Some versions of SDL before <2.0.10 appears to have performance/stalling issues on a minority of Windows systems, 
+    // depending on whether SDL_INIT_GAMECONTROLLER is enabled or disabled.. updating to latest version of SDL is recommended!)
     if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER | SDL_INIT_GAMECONTROLLER) != 0)
     {
         printf("Error: %s\n", SDL_GetError());