add ~riscv keyword
tatt test repot: USE tests started on Thu Oct 13 14:17:51 -00 2022 FEATURES=' test' USE='' succeeded for =sys-fs/mergerfs-2.33.5 USE='-xattr' succeeded for =sys-fs/mergerfs-2.33.5
and the mergerfs-tools tatt test report: USE tests started on Thu Oct 13 14:48:21 -00 2022 FEATURES=' test' USE='' succeeded for =sys-fs/mergerfs-tools-0_p20210502-r3
Looks good to me.
Pull request merged.