/usr/lib/x86_64-linux-gnu/libmhash.so is in libmhash-dev 0.9.9.9-7.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libmhash.so.2.0.1
/usr/lib/x86_64-linux-gnu/libmhash.so.2.0.1