libgcc9 build failure on macOS Monterey (12.2) Xcode 13.2.1

[MarkCallow (Mark Callow)]

In what has turned into a very painful migration of my MacPort's installed packages from Big Sur to Monterey I have found that the package libgcc9 won't build. There are "Undefined symbols for architecture x86_64:", when linking gencondmd.o. Here is the list. I will upload the complete log file.

:info:build Undefined symbols for architecture x86_64:
:info:build   "_cfun", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_epilogue_completed", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_flag_cf_protection", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_flag_finite_math_only", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_flag_fp_int_builtin_inexact", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_flag_peephole2", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_flag_pic", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_flag_rounding_math", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_flag_trapping_math", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_flag_unsafe_math_optimizations", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_insn", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_ix86_arch_features", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_ix86_cmodel", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_ix86_fpmath", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_ix86_isa_flags", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_ix86_isa_flags2", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_ix86_pmode", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_ix86_tls_dialect", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_ix86_tune_features", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_operands", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_optimize", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_reload_completed", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_reload_in_progress", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_rtx_class", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_target_flags", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_this_target_flag_state", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o
:info:build   "_x86_prefetch_sse", referenced from:
:info:build       ___cxx_global_var_init.99 in gencondmd.o

A half-dozen or so of the packages I had installed on Big Sur have a dependency on libgcc9 so I'm stuck.

[MarkCallow (Mark Callow)]

Log of failed build of libgcc9 package.

[MarkCallow (Mark Callow)]

I've just been told this problem is being tracked in issue #64316. My search failed to find that because I searched for "libgcc9" and #64316 refers to "gcc9". I am unable to mark this as a duplicate, probably due to lack of permissions.