Update firewallcheck.cpp
Update firewallcheck.cpp

Allow compile on non-windows
docsteer/sacnview,docsteer/sacnview,docsteer/sacnview,marcusbirkin/sacnview,marcusbirkin/sacnview,marcusbirkin/sacnview,marcusbirkin/sacnview,docsteer/sacnview,marcusbirkin/sacnview,docsteer/sacnview,marcusbirkin/sacnview,marcusbirkin/sacnview,docsteer/sacnview,docsteer/sacnview