[MacPorts] #73607: mas: Restrict to supported OS versions

[MacPorts]

#73607: mas: Restrict to supported OS versions
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  Reporter:  ryandesign  |      Owner:  kimuraw
      Type:  defect      |     Status:  assigned
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:  2.12.3
Resolution:              |   Keywords:
      Port:  mas         |
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Comment (by ryandesign):

 I do not see any such swift ports when I
 [https://ports.macports.org/search/?q=swift&name=on search]. Providing
 ports for newer versions of swift and providing a portgroup or
 enhancements to base to allow ports to specify a required version of
 swift, causing dependencies on those ports to be added and doing whatever
 else is necessary to direct the build to use them, sound like excellent
 opportunities for someone to contribute.

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Ticket URL: <https://trac.macports.org/ticket/73607#comment:2>
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