[MacPorts] #64562: "libgcc9 cannot be built while libunwind-headers is active." when migrating from Big Sur to Monterey

[MacPorts]

#64562: "libgcc9 cannot be built while libunwind-headers is active." when migrating
from Big Sur to Monterey
-------------------------+--------------------
  Reporter:  MarkCallow  |      Owner:  (none)
      Type:  defect      |     Status:  new
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:  2.7.1
Resolution:              |   Keywords:
      Port:              |
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Comment (by MarkCallow):

 There was only one occurrence of `gcc9` in `myports.txt` which was in the
 line for installing libgcc9. I deleted it but, even with that gone and
 gcc11 manually installed, there were still several attempts to install
 libgcc9 as a dependency. Bizarrely the source of that dependency appears
 to be libgcc8 and gcc8. I deleted libgcc8 and gcc8 from `myports.txt` too
 and after that no more build problems. I finally have my ports migrated.

 Thanks for your great help @kencu. The workaround you provided is
 sufficient. If there is nothing that can be done to restore_ports to help
 with the libunwind_headers issue then you may as well close this issue.

-- 
Ticket URL: <https://trac.macports.org/ticket/64562#comment:11>
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