[Coco] WIP XRoar composite video support

[Ciaran Anscomb]

Allen Huffman via Coco wrote:
> 
> I’d need to know more details, since the vast majority of stuff I
> am running from open sources (homebrew, macports, etc.) are Linux
> items. Since I am currently looking at doing some GUI photo processing
> apps, and want to make them cross platform, this is a topic that is of
> interest to me :)

Does MacOSX+ still ship with XQuartz?  If so, and if there's a port of
GTK+ 2 (which is _old_ now), AND if libgtkglext works with it, you might
be able to get it to work?

Alternately, if there are mac devs here that know how to piece a
dialog box together with all the right bits that doesn't require some
mac-specific tool, maybe it wouldn't be too much work...

..ciaran