Ports Who Link Differently Due to GTK quartz/x11

[Jeremy Lavergne]

Do we have any mechanism in place to handle rebuilding/switching ports
when GTK is built against x11 versus quartz?

>From what I can see, the best approach is to provide the x11/quartz
variants but have them do nothing: by switching the variants you end up
rebuilding (or downloading) the appropriate version of links against GTK.