Created attachment 701364 [details] /var/log/portage/dev-qt:qtpaths-5.15.2:20210421-061417.log CXX at the time of build is: x86_64-pc-linux-gnu-g++-10.3.0 Yet the build system gets 10.2.0 from somewhere and uses that instead.
Created attachment 701367 [details] emerge-info.txt