[Bug c/89051] -Wno-error= does not work for warning groups

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89051

--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
LangEnabledBy is used by optc-gen.awk to generate options.c with calls like
those below.  Other than that, I don't think GCC has an internal data structure
to represent this relationship (one that could be queried to give a list of
other options that -Wimplicit controls).  But I'm by no means an expert on
option processing.

    case OPT_Wimplicit:
      if (!opts_set->x_warn_implicit_function_declaration)
        handle_generated_option (opts, opts_set,
                                 OPT_Wimplicit_function_declaration, NULL,
value,
                                 lang_mask, kind, loc, handlers, true, dc);
      if (!opts_set->x_warn_implicit_int)
        handle_generated_option (opts, opts_set,
                                 OPT_Wimplicit_int, NULL, value,
                                 lang_mask, kind, loc, handlers, true, dc);
      break;