Currently this requires the X11 headers, but there are a number of methods that we could use on other platforms, ie: the gtk selectiondata workaround from #1579. This would also make it easier to port to python3 / GTK3 (#1568)
The split is needed to fix the gtk selectiondata workaround on osx: #318
Done in r16535.
There isn't much that can be moved, but at least the separation is clean.
For example, the gdk_atoms
code (also used by the clipboard) is GTK2 only.
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1588