It looks like another problem. This is a C++ name-mangled symbol, and you can reverse the mangling and see what it is by
# c++filt _ZTIN18KDockWidget_Compat15KDockMainWindowE
typeinfo for KDockWidget_Compat::KDockMainWindow
That means that your code has been compiled with run-time type information (rtti), while the existing libraries on your system have ben compiled without, and now your code wants that rtti symbol and doesn't find it. Trust me, it's just the *first one* it doesn't find. There will be hundreds of other undefined symbols.
rtti is on by default with g++, you can disable it with
g++ -fno-rtti. Just make clean and add that switch to the setup, then compile again.
It's ok if the libraries you link with have it and your code doesn't, then it's just sitting in the libs and isn't used, but it doesn't work the other way around. But it's better to have it consistent.
Hope it helps,