Initialise variable 'start' at the beginning

src/main.c

@@ -6,6 +6,7 @@
 int main (int argc, char* args[])
 {
   Pong *p = NULL;
+    int start = false;
 
     if (SDL_Init(SDL_INIT_VIDEO) < 0)
     {
@@ -16,7 +17,6 @@ int main (int argc, char* args[])
     p = Pong_init();
     Pong_render(p);
 
-    int start = false;
     while (!start) {
       printf("Press any key to start...\r");
       fflush(stdout);