Check standard error code return values as < 0 instead of == -1

test/testurl.c

@@ -25,7 +25,7 @@ static void tryOpenURL(const char *url)
 int main(int argc, char **argv)
 {
     int i;
-    if (SDL_Init(SDL_INIT_VIDEO) == -1) {
+    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
         SDL_Log("SDL_Init failed: %s\n", SDL_GetError());
         return 1;
     }