[Request] Please fix missing pgtk clipboard functionality

[Timothy]

Hello all,

I’ve been interested in adding rich clipboard support to org-mode (with
yank-media), but it seems that as a pgtk user this functionality is unavailable
to me. For instance, `(gui-get-selection =CLIPBOARD =TARGETS)' always returns 
`nil'
for me.

If pgtk could be put on equal footing with X in this regard, that would be much
appreciated.

All the best,
Timothy