[MacPorts] #52355: darwinbuild: update for move to GitHub

[MacPorts]

#52355: darwinbuild: update for move to GitHub
--------------------------+-------------------
  Reporter:  e-t-h-a-n    |      Owner:  wms@…
      Type:  update       |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.3.4
Resolution:               |   Keywords:
      Port:  darwinbuild  |
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Changes (by kencu):

 * Attachment "patch-darwinbuild.diff" added.

 Portfile patch version 20170521

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Ticket URL: <https://trac.macports.org/ticket/52355>
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