Package:Fchroot

root # 
echo 'QEMU_USER_TARGETS="aarch64 arm"' >> /etc/portage/make.conf
echo "app-emulation/qemu static-user qemu_user_targets_aarch64 qemu_user_targets_riscv64 qemu_user_targets_arm" >> /etc/portage/package.use
echo "dev-libs/glib static-libs" >> /etc/portage/package.use
echo "dev-libs/libpcre static-libs" >> /etc/portage/package.use
echo "sys-apps/attr static-libs" >> /etc/portage/package.use
emerge -av fchroot

add sandboxing to the raspberry pi make.conf

   /mnt/funtoo/etc/portage/make.conf - add sandbox

FEATURES="-pid-sandbox"