@narodnik @evoskuil The ringsignature branch build failure is simply because master's install.sh isn't updated to version5 of secp256k1 (it's still at version4; libbitcoin version3 install.sh is correctly updated to secp256k1 version5).
@narodnik if you swap that out in the install.sh file and push it, travis-ci should just rebuild everything properly. Reference:
https://github.com/libbitcoin/libbitcoin/blob/master/install.sh#L759