Run `src/qt/bitcoin-qt --disablewallet=1`. 
Quitting after any amount of time will result in `Segmentation fault: 11`

0.14.0 branch at 861cb0c83db0571c2863f6b6276314e115c266ee , osx 10.12.3, Qt5.8
{
    if (_optionsModel)
    {
        this->optionsModel = _optionsModel;
        
        connect(_optionsModel,SIGNAL(displayUnitChanged(int)),this,SLOT(updateDisplayUnit(int)));
        
        updateDisplayUnit(_optionsModel->getDisplayUnit());
    }
}
void UnitDisplayStatusBarControl::updateDisplayUnit(int newUnits)
{
    setText(BitcoinUnits::name(newUnits));
}
void UnitDisplayStatusBarControl::onDisplayUnitsClicked(const QPoint& point)
{
    QPoint globalPos = mapToGlobal(point);
    menu->exec(globalPos);
}
void UnitDisplayStatusBarControl::onMenuSelection(QAction* action)
{
    if (action)
    {
        optionsModel->setDisplayUnit(action->data());
    }
}