[MacPorts] #66751: snac @2.18: use the right compiler and flags

[MacPorts]

#66751: snac @2.18: use the right compiler and flags
-------------------------+----------------------
  Reporter:  ryandesign  |      Owner:  artkiver
      Type:  defect      |     Status:  assigned
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:  2.8.0
Resolution:              |   Keywords:
      Port:  snac        |
-------------------------+----------------------

Comment (by artkiver):

 Well, what "worksforme" on my local system apparently made the build bots
 unhappy when I submitted a PR:

 e.g.

 https://github.com/macports/macports-
 ports/actions/runs/4021961917/jobs/6911272754
 https://github.com/macports/macports-
 ports/actions/runs/4021961917/jobs/6911272700

 I can, presumably, revert to an even more conservative Portfile version
 bump and I am guessing it would pass the CI checks OK, but probably not
 adequately address the concerns raised here.

-- 
Ticket URL: <https://trac.macports.org/ticket/66751#comment:3>
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