Please keyword dev-embedded/xa for ~arm ~arm64. This package is a build time dependency for the VICE emulator. The VICE emulator is very widely deployed on 32 and 64 bit ARM systems, especially on the Raspberry Pi. This is related to bug #861008 a request to keyword app-emulation/vice for ~arm and ~arm64.
It's okay to do them in the same bug if dependencies, especially as if one fails, we may not want to bother with the other. *** This bug has been marked as a duplicate of bug 861008 ***