While testing 17270 I noticed that master (bdda137878904e9401a84e308ac74c93c2ef87c1) does not run on NetBSD. I assume this started after #17085 changed the fallback locale from `C` to `C.UTF-8`. There doesn't seem to be a `C.UTF-8` locale on NetBSD.

```bash
src/bitcoind
terminate called after throwing an instance of 'std::runtime_error'
  what():  locale::facet::_S_create_c_locale name not valid
Abort trap (core dumped)
```

`LC_ALL=C src/bitcoind` works, `LC_ALL=en_US.UTF-8 src/bitcoind` does not.

```bash
locale
LANG=""
LC_CTYPE="en_US.UTF-8"
LC_COLLATE="C"
LC_TIME="C"
LC_NUMERIC="C"
LC_MONETARY="C"
LC_MESSAGES="C"
LC_ALL=""
```
}
        
        if (arg_map.first == OptionsCategory::HIDDEN) break;
        for (const auto& arg : arg_map.second) {
            if (show_debug || !(arg.second.m_flags & ArgsManager::DEBUG_ONLY)) {
                std::string name;
                if (arg.second.m_help_param.empty()) {
                    name = arg.first;
                } else {
                    name = arg.first + arg.second.m_help_param;
                }
                usage += HelpMessageOpt(name, arg.second.m_help_text);
            }
        }
    }
    return usage;
}
bool HelpRequested(const ArgsManager& args)
{
    return args.IsArgSet("-?") || args.IsArgSet("-h") || args.IsArgSet("-help") || args.IsArgSet("-help-debug");
}
void SetupHelpOptions(ArgsManager& args)
{
    args.AddArg("-?", "Print this help message and exit", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
    args.AddHiddenArgs({"-h", "-help"});
}
static const int screenWidth = 79;
static const int optIndent = 2;
static const int msgIndent = 7;
std::string HelpMessageGroup(const std::string &message) {