libgcc7 build failed (MacOS Big Sur)

[clegra]

under MacOS 11.7.10, libgcc7 repeatedly fails to build

--->  Building libgcc7
Error: Failed to build libgcc7: command execution failed 
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_lang_gcc7/libgcc7/main.log for details.
Error: Problem while installing libgcc7
Error: rev-upgrade failed: Error rebuilding gcc7

[clegra]

log file referred to in the error message of libgcc7 build fail

[clegra]

while a prompt sometimes says that "libgcc7 is known to fail" and asks whether I want to build it, it is used/referred to for the installation of subversion which I need.

-- many thanks in advance for all indications and help

[ryandesign (Ryan Carsten Schmidt)]

gcc7 and libgcc7 are indeed for OS X 10.10 and earlier. They are not expected to be compatible with later macOS versions. Use a newer gcc port instead.

The error in the log is:

/usr/bin/clang++ -arch x86_64 -std=gnu++98   -g  -DIN_GCC    -fno-strict-aliasing -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wno-format -Wmissing-format-attribute -Woverloaded-virtual -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -fno-common  -DHAVE_CONFIG_H -DGENERATOR_FILE -fno-PIE -L/opt/local/lib -Wl,-headerpad_max_install_names -Wl,-syslibroot,/Library/Developer/CommandLineTools/SDKs/MacOSX11.sdk -no-pie -o build/gencondmd \
	    build/gencondmd.o ../build-x86_64-apple-darwin20/libiberty/libiberty.a
clang: warning: argument unused during compilation: '-no-pie' [-Wunused-command-line-argument]
Undefined symbols for architecture x86_64:
  "_cfun", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_epilogue_completed", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_flag_finite_math_only", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_flag_fp_int_builtin_inexact", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_flag_peephole2", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_flag_pic", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_flag_rounding_math", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_flag_trapping_math", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_flag_unsafe_math_optimizations", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_insn", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_arch_features", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_cmodel", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_fpmath", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_indirect_branch_register", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_isa_flags", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_isa_flags2", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_pmode", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_stack_protector_guard", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_tls_dialect", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ix86_tune_features", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_operands", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_optimize", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_ptr_mode", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_reload_completed", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_reload_in_progress", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_rtx_class", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_target_flags", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_this_target_flag_state", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_word_mode", referenced from:
      ___cxx_global_var_init in gencondmd.o
  "_x86_prefetch_sse", referenced from:
      ___cxx_global_var_init in gencondmd.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[3]: *** [build/gencondmd] Error 1
make[3]: *** Waiting for unfinished jobs....

Nothing in the dependency chain of the subversion port requires any gcc port—not with default variants on macOS 12 anyway.