Extract correct signedness for flagged enum types

    enum PositioningMethod {
        NoPositioningMethods = 0x00000000,
        SatellitePositioningMethods = 0x000000ff,
        NonSatellitePositioningMethods = 0xffffff00,
        AllPositioningMethods = 0xffffffff
    };
    Q_DECLARE_FLAGS(PositioningMethods, PositioningMethod) 

// qml

...
property int a: PositioningMethod.NonSatellitePositioningMethods
property enumtype b: a


console.log("bound to int",a); // Prints -256
console.log("enum", PositionSource.NonSatellitePositioningMethods); // Prints -256
console.log("bound to Enum", b); // Prints -256

console.log("bound to Enum", b); // Prints 4294967040