[MacPorts] #62878: openmpi: mark subports as known_fail on appropriate OS versions

[MacPorts]

#62878: openmpi: mark subports as known_fail on appropriate OS versions
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 Reporter:  jmroot  |      Owner:  mascguy
     Type:  defect  |     Status:  assigned
 Priority:  Normal  |  Milestone:
Component:  ports   |    Version:
 Keywords:          |       Port:  openmpi
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 A lot of the subports of openmpi fail to build on some subset of OS
 versions. For example, openmpi-gcc10 fails on 10.7 and 10.8:
 https://ports.macports.org/port/openmpi-gcc10/builds

 Ideally all the build failures would be fixed of course, but until and
 unless that happens, each subport should set `known_fail yes` on platforms
 where it is failing. Otherwise the buildbot wastes a lot of time running a
 new build of all the subports that previously failed each time the
 Portfile is modified in any way.

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Ticket URL: <https://trac.macports.org/ticket/62878>
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