osx modulesets for building GTK3 + gobject-introspection bindings

[totaam]

To be done after Xpra-org/xpra#533, with which it will share a lot of definitions.

This will allow us to test the GTK3 build on osx. (see Xpra-org/xpra#90 and Xpra-org/xpra#640)

The moduleset should be updated with (some we don't even use, but update for consistency):

• libffi 3.1
• gobject-introspection 1.40.0
• gtk+ 3.12.2
• Python-3.4.1
• pygobject 3.12.2
• gnome-icon-theme 3.12.0
• gnome-icon-theme-symbolic 3.12.0
• gnome-icon-theme-extras 3.12.0
• gnome-themes-standard 3.12.0

See also the updates in Xpra-org/xpra#533#comment:43.

(removed: just noticed that apr and apr-util are duplicated)

[totaam]

See also: Xpra-org/gtk-osx-build#13 "64-bit builds for osx"

I am re-scheduling because I am losing faith in GTK. Maybe a native pyobjc port would be better...

[totaam]

Done the updates as part of python3 packaging for macos (#1575), see Xpra-org/xpra#1575#comment:9.