[MacPorts] #69016: Add Flang as fortran compiler for mpich-clang

[MacPorts]

#69016: Add Flang as fortran compiler for mpich-clang
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  Reporter:  rfj82982        |      Owner:  (none)
      Type:  defect          |     Status:  new
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:  2.8.1
Resolution:                  |   Keywords:  mpich-clang, openmpi-clang
      Port:  mpich-clang-17  |
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Comment (by kencu):

 flang is not considered ready for general use yet, although it continually
 gets closer.

 Maybe late 2024, or 2025?

 Here’s an example of many status documents you can find:

 https://linaro.atlassian.net/wiki/spaces/LLVM/pages/28687990785/Flang+support+in+LLVM+FLANG

 Generally speaking, MacPorts tries not to use compilers and toolchains
 that are broken/not ready, as build errors and bugs show up, and useless
 tickets get opened because we are not flang developers and can’t fix them.

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Ticket URL: <https://trac.macports.org/ticket/69016#comment:1>
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