randtype: mark as broken on darwin

pkgs/games/randtype/default.nix

···
     maintainers = with maintainers; [ dandellion ];
     license = licenses.gpl2Only;
     platforms = platforms.unix;
+    broken = stdenv.isDarwin; # never built on Hydra https://hydra.nixos.org/job/nixpkgs/trunk/randtype.x86_64-darwin
   };
 }