I suspect that is due to QT version 5.5 which I am not able upgrade on my system.
I have tried to work around this problem by changing QOverload with static_cast but I wonder how many lines of code I need to change.
When was QOverload’ used first time? I was able to compile Kstars in January 2020.
Where can I find last version without QOverload?
I managed to compile indi an Kstars 3.5 on my system very old ubuntu 16.04 ..
I needed only to change 3 source files in kstars/ekos/align/align.cpp, optionsprofileeditor.cpp, and kstars/ekos/ focus/focus.cpp (around 10 lines of code) by substituting QOverload with static_cast. (for those who need to do this: change "QOverload<YYY &>::of(&XXX" "static_cast<void (XXX::*)(YYY)>(&XXX" whery YYY is type and XXX name.