sub require_module($) {
        # Localise %^H to work around [perl #68590], where the bug exists
        # and this is a satisfactory workaround.  The bug consists of
        # %^H state leaking into each required module, polluting the
        # module's lexical state.
        local %^H if _WORK_AROUND_HINT_LEAKAGE;
        if(_WORK_AROUND_BROKEN_MODULE_STATE) {
                my $notional_filename = &module_notional_filename;
                my $guard = bless([ $notional_filename ],
                                "Module::Runtime::__GUARD__");
                my $result = CORE::require($notional_filename);
                pop @$guard;
                return $result;
        } else {
                return scalar(CORE::require(&module_notional_filename));
        }
}