[MacPorts] #15712: Add versions to platforms

[MacPorts]

#15712: Add versions to platforms
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  Reporter:  raimue       |      Owner:  larryv
      Type:  enhancement  |     Status:  assigned
  Priority:  Normal       |  Milestone:  MacPorts 2.6.0
 Component:  base         |    Version:
Resolution:               |   Keywords:
      Port:               |
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Comment (by raimue):

 We can certainly check whether the current platform is supported when
 trying to install a port. This would be the same what we already do for
 `supported_archs`.

 However, checking the whole dependency tree before attempting to install
 any port, even any dependency, should only be attempted with the libsolv
 branch as that inherently collects the whole dependency tree first.

-- 
Ticket URL: <https://trac.macports.org/ticket/15712#comment:35>
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