Thanks for the hint. That's what the alpha is for, getting the glitches clarified.
For the Makefile issue:
To be honest, I have not much experience in doing the makefiles, so in case we have customized environment, I'm a bit lost what to do.
But so far, there should not be the need to adjust the Makefile, only the qmake ".pro" files need to be adjusted.
For Linux, the respective .pro settings are in the file "src/src.pro".
Maybe I will switch to cmake, but also there no experience on my side.