The zn_poly package prior to version 0.9.2-2 was missing a soname link. This has been fixed in 0.9.2-2, so the upgrade will need to overwrite the untracked files created by ldconfig. If you get an error
zn_poly: /usr/lib/libzn_poly-0.9.so exists in filesystem
when updating, use
pacman -Syu --overwrite usr/lib/libzn_poly-0.9.so
to perform the upgrade.