[SDL2] pointer boolean (#8523)

test/testdrawchessboard.c

@@ -106,13 +106,13 @@ int main(int argc, char *argv[])
 
     /* Create window and renderer for given surface */
     window = SDL_CreateWindow("Chess Board", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480, SDL_WINDOW_RESIZABLE);
-    if (window == NULL) {
+    if (!window) {
         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Window creation fail : %s\n", SDL_GetError());
         return 1;
     }
     surface = SDL_GetWindowSurface(window);
     renderer = SDL_CreateSoftwareRenderer(surface);
-    if (renderer == NULL) {
+    if (!renderer) {
         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Render creation for surface fail : %s\n", SDL_GetError());
         return 1;
     }