[MacPorts] #62807: openmpi/mpich: refactor duplicated logic, and simplify ports, via new portgroup

[MacPorts]

#62807: openmpi/mpich: refactor duplicated logic, and simplify ports, via new
portgroup
----------------------------+----------------------
  Reporter:  mascguy        |      Owner:  mascguy
      Type:  enhancement    |     Status:  assigned
  Priority:  Normal         |  Milestone:
 Component:  ports          |    Version:
Resolution:                 |   Keywords:
      Port:  openmpi mpich  |
----------------------------+----------------------

Comment (by kencu):

 I am not aware of any reason to keep support for gcc older than gcc7.

 Anyone using a macports-clang probably wants at least macports-clang-9.0
 by this point, but I don't know if there might be some niche user with an
 old code base that uses some older macports-clang for something.

 maybe deprecate them in some way? Or just bin them?

-- 
Ticket URL: <https://trac.macports.org/ticket/62807#comment:7>
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