[MacPorts] #60511: gtk3, pango and cairo: move to quartz as default backend

[MacPorts]

#60511: gtk3, pango and cairo: move to quartz as default backend
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  Reporter:  ra1nb0w             |      Owner:  dbevans
      Type:  enhancement         |     Status:  assigned
  Priority:  Normal              |  Milestone:
 Component:  ports               |    Version:
Resolution:                      |   Keywords:
      Port:  gtk3, pango, cairo  |
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Comment (by michaelld):

 I like this idea, as it reduces a set of dependencies for GTK3 (etc).
 Progress has been made on these ports to make them work with Quartz even
 better than their predecessors (GTK2 etc) ... so why not embrace this
 usage of them?

 Of course, any port that uses GTK3 (etc) that -requires- Quartz or X11
 must do a variant check. Those that can go either way could add variants
 to do the checking. Or, they can just use GTK3 (etc) as they are
 installed. There are options ...

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Ticket URL: <https://trac.macports.org/ticket/60511#comment:1>
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