[MacPorts] #61667: mpir fails to build on Big Sur

[MacPorts]

#61667: mpir fails to build on Big Sur
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  Reporter:  alex1platon  |      Owner:  (none)
      Type:  defect       |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.6.4
Resolution:               |   Keywords:  mpir big sur
      Port:  mpir         |
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Comment (by alex1platon):

 sorry only now did I see #61560 , seems seems to duplicate it.  must have
 been blind when I first searched for open tickets.  please delete /merge

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Ticket URL: <https://trac.macports.org/ticket/61667#comment:1>
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