Test on macOS 12.2.1 against the master branch. #24397 doesn't fix it.

```
brew info boost
boost: stable 1.78.0 (bottled), HEAD
...
./configure --enable-external-signer
...
checking for boostlib >= 1.64.0 (106400)... yes
checking whether Boost.Process can be used... no
configure: error: External signing is not supported for this Boost version
```

It does work with boost 1.76 (there was no 1.77 release in home-brew):

```
brew install boost@1.76
...
LDFLAGS="-L/usr/local/opt/boost@1.76/lib" CPPFLAGS="-I/usr/local/opt/boost@1.76/include" ./configure --enable-external-signer
...
checking for boostlib >= 1.64.0 (106400)... yes
checking whether Boost.Process can be used... yes
...
Options used to compile and link:
  external signer = yes
```

There's nothing in the release notes about Boost.Process for either [1.77](https://www.boost.org/users/history/version_1_77_0.html) or [1.78](https://www.boost.org/users/history/version_1_78_0.html).

The Homebrew [formula changes](https://github.com/Homebrew/homebrew-core/commits/master/Formula/boost.rb) are nothing but a trivial version and hash bump.
}
        
        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) {