Source: witty Version: 3.3.6+dfsg-1.1 Severity: serious libwtdbomysql40 has a hard-coded dependency on libmysqlclient18 but that library is no longer built from source in Debian stretch.
I believe the appropriate dependency ( libmariadbclient18 now that the default MySQL is MariaDB ) is already automatically added during the build. Thanks, Jeremy Bicha