[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):

 > disable the dep on clang7 in the gcc9 portfile, deactivate clang7, then
 try again.

 The "deactivate" part I get (I don't have clang-7.0 any more, would need
 to deactivate clang-8.0 ;) - but how do I disable something in a
 Portfile???



 > does it fail on the buildbots?

 I've no idea.


 > why aren't you getting a prebuilt binary anyway?

 Ah, this is the question I'd love to learn the answer. I seem to recall
 that most (all?) of the previous gcc8 (and gcc7?) updates were downliaded
 as prebuilt binaries. There are no variants to this port. So, WTF? Why
 **doesn't** it pull the prebuilt binaries?

-- 
Ticket URL: <https://trac.macports.org/ticket/58442#comment:6>
MacPorts <https://www.macports.org/>
Ports system for macOS