I ran into this, but this is not all.
I'm on slackware 14.2, where i managed to get QT5 working, just to have FlatCAM working. Before this I was using 0.18 from about a year ago, and I was using the same slackbuild. It somehow went ok, but it used the pyside not pyside2, so I got this error. Other than that, it looked like qt5 is working, path wb is working and just the tool table edit showed the symptoms described. The dependencies are all shitty, and my problem is different.
I can't get qt-everywhere-src-5.13.0-rc3 to produce the webkit, which is required by pyside-setup (if I understand it correctly it should build the pyside2).
It is configured and builds, but the webkit is just not there. At qtwebengine subdir, when poking around with make, "make qmake" produces the error:
"C++14 support is required in order to build chromium. QtWebEngine will not be built." this is any kind of info, but gcc 5.3.0 should support this, and configure does not see any problem. What is even more crazy, webkits configure.pri has checks for python version, and "Python version 3 is not supported by Chromium." does not make much sense if I am about to build the webkit to have support for python3...
Any ideas? Anyone using slackware or derivatives? Any working version combination? The compilation takes about two days, and this is just awful.
I already have linuxcnc running on this distro, or maybe should I use another one? If so, which one would not be a huge slow crap, has possible support for 32bit, is linuxcnc compatible and will just support qt5/python3 for fresh FreeCAD build?