[MacPorts] #58442: gcc9 (and other gccN) fails to install on Mojave, Xcode-10.2.1

[MacPorts]

#58442: gcc9 (and other gccN) fails to install on Mojave, Xcode-10.2.1
-------------------------+--------------------
  Reporter:  mouse07410  |      Owner:  (none)
      Type:  defect      |     Status:  new
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:
Resolution:              |   Keywords:
      Port:  gcc9        |
-------------------------+--------------------

Comment (by mouse07410):

 Assuming I'm correct (I think I am), and {{{xcode}}} is not the default
 variant for {{{cctools}}} - would it make sense to ''make'' it default? If
 so, could somebody push that change please?

 I'm still planning to run the experiments we talked above, but will set a
 MacOS VM for that first.

-- 
Ticket URL: <https://trac.macports.org/ticket/58442#comment:16>
MacPorts <https://www.macports.org/>
Ports system for macOS