Fix -Wunused-argument for generated C stubs for bytecode

[dannywillems]

This is a draft, untested. Related to https://github.com/yallop/ocaml-ctypes/issues/248#issuecomment-1440045648

[dannywillems]

Running find . -name "*stubs*.c" | xargs grep "argc" after make && make test gives some generated stubs. Picking randomly ./tests/test-returning-errno-lwt-jobs/generated_stubs.c and checking it is fine:

Before:

value cstubs_tests_2_sixargs_byte6 (value *argv, int argc)
{
  return
    cstubs_tests_2_sixargs(argv[0], argv[1], argv[2], argv[3], argv[4],
                           argv[5]);
}

value cstubs_tests_2_sixargs_byte6 (value *argv, int argc)
{
  (void)(argc);
return
                  cstubs_tests_2_sixargs(argv[0], argv[1], argv[2], argv[3],
                                         argv[4], argv[5]);
}

Do we want a better formatting?

Also, I don't see any make rules to compile the C code to check we can compile. Can you help me? IMO, the MR is ready. Changing the title.

[yallop]

Do we want a better formatting?

Yes; it looks better after 66d1bfd:

value cstubs_tests_2_sixargs_byte6 (value *argv, int argc)
{
  (void)(argc);
  return
    cstubs_tests_2_sixargs(argv[0], argv[1], argv[2], argv[3], argv[4],
                           argv[5]);
}

You may need to rebuild from clean to see it. I'm not sure the test build rules capture the dependencies precisely enough to pick up the change in the cstubs library.

Also, I don't see any make rules to compile the C code to check we can compile. Can you help me?

The rules are in Makefile.rules (e.g.) and Makefile.tests. Running make test is sufficient to build the generated C code. The object file for tests/test-returning-errno-lwt-jobs/generated_stubs.c should be in _build/tests/test-returning-errno-lwt-jobs/generated_stubs.o.

[yallop]

Thank you!