[MacPorts] #62789: openmpi: remove subports for clang 3.3 and 3.4

[MacPorts]

#62789: openmpi: remove subports for clang 3.3 and 3.4
---------------------+----------------------
 Reporter:  mascguy  |      Owner:  mascguy
     Type:  defect   |     Status:  assigned
 Priority:  Normal   |  Milestone:
Component:  ports    |    Version:
 Keywords:           |       Port:  openmpi
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 Presently, `openmpi` provides subports for the following clang 3.x
 versions:
 * 3.3
 * 3.4
 * 3.7

 That's in addition to clang 5 through 11.

 The clang 3.x subports have the following usage statistics, over the past
 365 days:
 * openmpi-clang33 - zero installs
 * openmpi-clang34 - zero installs
 * openmpi-clang37 - one install

 Of note, sibling MPI port `mpich` doesn't provide subports for clang 3.x
 versions; only for 5 through 11.

 It's suggested that we remove the subports for clang 3.3 and 3.4, given
 the usage stats.

-- 
Ticket URL: <https://trac.macports.org/ticket/62789>
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