[MacPorts] #55153: armadillo @8.200.1 +arpack: 'mpi.h' file not found

[MacPorts]

#55153: armadillo @8.200.1 +arpack: 'mpi.h' file not found
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  Reporter:  majoc-at-astro  |      Owner:  Schamschula
      Type:  defect          |     Status:  assigned
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:  2.4.2
Resolution:                  |   Keywords:
      Port:  armadillo       |
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Comment (by majoc-at-astro):

 Replying to [comment:2 Schamschula]:
 > You are building arpack +mpi. armadillo assumes arpack w/o +mpi.

 Not explicitly:
 {{{
 port install arpack +gcc6
 }}}
 But now I look, I find openmpi-gcc6 installed further up the build list
 for other purposes, though None is selected as gcc at the point arpack is
 built.  That might explain why I haven't managed to reproduce the problem
 in test builds.

 Please stand by.  That's given me a bunch of things to try.

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Ticket URL: <https://trac.macports.org/ticket/55153#comment:4>
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