missing wl_proxy_marshal_flags on PyQt6 >= 6.5.1

[Colin Macdonald]

Hi Phil,

Apparently Debian 11 ships an older version of Wayland, and anything >= 
6.5.0 does not work

/home/cbm/.local/lib/python3.9/site-packages/PyQt6/Qt6/plugins/platforms/../../lib/libQt6WaylandClient.so.6: 
undefined symbol: wl_proxy_marshal_flags

I hit this when running to run PyQt6 on Chrome OS but it seems like it 
effects WSL2 and anyone using Debian 11:

https://bugreports.qt.io/browse/QTBUG-114635

This is issue apparently that Debian 11 does not have wayland >= 1.19.91.

I have verified that `pip install PyQt6==6.5.0 PyQt6-Qt6==6.5.0` works 
fine on Chrome OS.  6.5.1, 6.5.3 and 6.6.0 do not.  Even with Flatpak, 
I get crashes about this symbol as soon as I close any window.

best,
Colin

-- 
Colin Macdonald
Associate Professor
Dept of Math, UBC