[MacPorts] #61435: use_xcode default value is incorrect on macOS 11.0

[MacPorts]

#61435: use_xcode default value is incorrect on macOS 11.0
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  Reporter:  nicst35  |      Owner:  (none)
      Type:  defect   |     Status:  new
  Priority:  Normal   |  Milestone:  MacPorts 2.6.4
 Component:  base     |    Version:  2.6.99
Resolution:           |   Keywords:  bigsur
      Port:           |
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Changes (by jmroot):

 * milestone:   => MacPorts 2.6.4


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Ticket URL: <https://trac.macports.org/ticket/61435#comment:3>
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