[MacPorts] #61477: clang-9.0 fails to build on Big Sur macOS 11.0.1 Xcode 12.2

[MacPorts]

#61477: clang-9.0 fails to build on Big Sur macOS 11.0.1 Xcode 12.2
------------------------+----------------------
  Reporter:  jhoyt4     |      Owner:  kencu
      Type:  defect     |     Status:  assigned
  Priority:  Normal     |  Milestone:
 Component:  ports      |    Version:
Resolution:             |   Keywords:
      Port:  clang-9.0  |
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Comment (by cjones051073):

 Replying to [comment:12 Tommaso93]:
 > I also have the clang-9.0 issue that is required by R and also root6.

 root6 does not depend on clang-{9,10}

 {{{
 Oberon-macOS-11 ~/Projects/MacPorts/ports > port rdeps root6 | grep clang
 Oberon-macOS-11 ~/Projects/MacPorts/ports >
 }}}

 if you are finding it is required in your build, you must have a non-
 default variant or something activated to cause it. Find that and remove
 it.

-- 
Ticket URL: <https://trac.macports.org/ticket/61477#comment:24>
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