[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 kencu):

 Here's a though. What variant of `cctools` do you have installed? I have
 the default, and most likely so does everyone else:
 {{{
 $ port -v installed cctools
 The following ports are currently installed:
   cctools @921_1+xcode (active) platform='darwin 18' archs='noarch'
 date='2019-01-28T13:27:12-0800'
 }}}

-- 
Ticket URL: <https://trac.macports.org/ticket/58442#comment:12>
MacPorts <https://www.macports.org/>
Ports system for macOS