winemac: Disable the zoom button for windows that are disabled.

[Ken Thomases]

Hi Kevin,

As mentioned in the other thread, I'm not seeing the problem that this is meant to solve on 10.6.  I will test 10.7+ tomorrow. Also, I'm pretty sure that setting the style mask after disabling the buttons can reenable them.  At least in some versions of the frameworks, we've seen that -setStyleMask: basically resets the standard buttons from scratch.  Indeed, in my testing, this patch reenables the close and minimize buttons on a disabled window.

Regards,
Ken