Don't spin as quickly as possible in the checkkeys rendering loop
diff --git a/test/checkkeys.c b/test/checkkeys.c
index 385b806..9167c5c 100644
--- a/test/checkkeys.c
+++ b/test/checkkeys.c
@@ -228,6 +228,9 @@ loop()
SDLTest_TextWindowDisplay(textwin, renderer);
SDL_RenderPresent(renderer);
+ /* Slow down framerate */
+ SDL_Delay(100);
+
#ifdef __EMSCRIPTEN__
if (done) {
emscripten_cancel_main_loop();