As packages are being ported, will become annoying if missing and do not wish people to opt for masking their USE=qt6 on these arches before doing a keywordreq. Hopefully works, PyQt6 has no tests so this is just going to check if it builds. Some extra dev-qt/* ppc* keywords needed due to USE being formerly masked for PyQt5, but both are pretty small and seeing little reason to skip unless they're broken.
arm done
ppc64 done
riscv done