[MacPorts] #40174: upgrade mingw and add win64 cross-compiler

[MacPorts]

#40174: upgrade mingw and add win64 cross-compiler
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  Reporter:  sam.halliday@…  |      Owner:  macports-tickets@…
      Type:  update          |     Status:  new
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:  2.2.0
Resolution:                  |   Keywords:
      Port:                  |
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Comment (by egall@…):

 As far as the "being quite old" part, that's #31578... as for the x86_64
 support part, I think I've seen a ticket for that, too, but I'm still
 looking for that...

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Ticket URL: <https://trac.macports.org/ticket/40174#comment:2>
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