The part of the GUI that this setting is relevant for does not exist in a `--disable-wallet` build. 

![wallet_prefs](https://user-images.githubusercontent.com/863730/70331435-72547300-180d-11ea-842d-82f8529ae982.png)
{
    ui->pruneWarning->setVisible(!ui->pruneWarning->isVisible());
}
void OptionsDialog::showRestartWarning(bool fPersistent)
{
    ui->statusLabel->setStyleSheet("QLabel { color: red; }");
    if(fPersistent)
    {
        ui->statusLabel->setText(tr("Client restart required to activate changes."));
    }
    else
    {
        ui->statusLabel->setText(tr("This change would require a client restart."));
        
        
        QTimer::singleShot(10000, this, &OptionsDialog::clearStatusLabel);
    }
}
void OptionsDialog::clearStatusLabel()