When you say a license to publish, do you mean you don't have a Mac to write it on? You don't need a license to write software for the Macintosh, just a mac :-)
I meant that I don’t have the Mac export module for Gamemaker:Studio(1), Apple developer account/certificates or a Mac to test and develop the game on. “License” just seemed an easier way to say it. It’s a good point thought, I need to look into ways to make the game more accessible.