8.0.0-alpha1 several QObject::connect: signal not found // compas not working

[atsju]

from #246 logs :

[2025-10-02 08:17:20.553] [warning] QT message handler: QObject::connect: signal not found in QwtCompass
[2025-10-02 08:17:20.572] [warning] QT message handler: QObject::connect: signal not found in QwtPlotPicker
[2025-10-02 08:17:20.921] [warning] QT message handler: QObject::connect: signal not found in QwtCompass

Those warnings are legit. And I haven't had time to check but it's possible those come from change in QWT version from 6.1.6 to 6.3.0 (required for QT6). Maybe some slots have been removed in newer Qwt version. I haven't found what. Maybe it's something totally different.

I also noted that the compas feature is not working in 8.0.0. Might be linked.

[atsju]

fixed in #252