"libgcc9 cannot be built while libunwind-headers is active." when migrating from Big Sur to Monterey

[MarkCallow (Mark Callow)]

I am trying to migrate my ports from Big Sur to Monterey. I'm exactly following the migration guide. While running restore_ports.tcl I get many instances of the subject error. The complete message is:

Error: libgcc9 cannot be built while libunwind-headers is active.
Error: Please forcibly deactivate libunwind-headers, e.g. by running:
Error: 
Error:     sudo port -f deactivate libunwind-headers
Error: 
Error: Then try again. You can reactivate libunwind-headers again later.
Error: Failed to configure libgcc9: libunwind-headers is active
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_lang_gcc9/libgcc9/main.log for details.

I tried sudo port -f deactivate libunwind-headers as suggested but the same thing happened next time I ran restore_ports.tcl. I then found closed ticket 59344 and following its suggestion I did sync and clean as well:

mark:~ $ sudo port sync
Password:
--->  Updating the ports tree
mark:~ $ sudo port -f deactivate libunwind-headers
--->  Deactivating libunwind-headers @5.0.1_0



--->  Cleaning libunwind-headers
mark:~ $ sudo port clean libgcc9
--->  Cleaning libgcc9
mark:~ $ sudo ./restore_ports.tcl myports.txt

But I still get the errors.

How can I migrate the affected ports?

[MarkCallow (Mark Callow)]

Log file mendtioned in the error message.