Hello, Carlos -
I've just built 4.2.2 on my linux machine and not encountered any of these issues: I don't get that warning; I can open files on the command line; and I can't get it to crash via the Eidos console.
The first thing I'd try is to do as it says:
export QT_QPA_PLATFORM=wayland
./SLiMgui
If that fixes the problem, then there are some threads related to that warning (e.g., this one:
https://forum.qt.io/topic/126731/what-is-this-warning/4 ) with some clues for what to do. If not, my suggestion is to remove it all and try installing again, paying extra attention to any
messages. My first suspicion is that you've not got the right version of QT, somehow. For further follow-up, I think we should move this to a github issue - could you open one (and email me)? We'll want to see the output of
dpkg-query -s cmake qt5-qmake qtchooser qtbase5-dev
and also exactly what commands make it crash.
good luck!
Peter