[MacPorts] #54747: m4 @1.4.18_2 fails to build on MacOS 10.13

[MacPorts]

#54747: m4 @1.4.18_2 fails to build on MacOS 10.13
----------------------+------------------------
  Reporter:  rex4539  |      Owner:
      Type:  defect   |     Status:  new
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:  2.4.99
Resolution:           |   Keywords:  highsierra
      Port:  m4       |
----------------------+------------------------

Comment (by blair):

 I'm not running High Sierra so any patches and fixes will need to be
 provided by people who are running the latest OS.

--
Ticket URL: <https://trac.macports.org/ticket/54747#comment:1>
MacPorts <https://www.macports.org/>
Ports system for macOS