[MacPorts] #56608: mpi portgroup needs to set configure.cxx_stdlib

[MacPorts]

#56608: mpi portgroup needs to set configure.cxx_stdlib
--------------------+--------------------
 Reporter:  jmroot  |      Owner:  (none)
     Type:  defect  |     Status:  new
 Priority:  Normal  |  Milestone:
Component:  ports   |    Version:
 Keywords:          |       Port:  hdf5
--------------------+--------------------
 Base doesn't know anything about the compilers used here, so the variants
 need to declare if they're using a different stdlib like macports-
 libstdc++.

 See: comment:ticket:56551:17

-- 
Ticket URL: <https://trac.macports.org/ticket/56608>
MacPorts <https://www.macports.org/>
Ports system for macOS