Package: libc-ares-dev Version: 1.10.0-2 The ares_set_servers_csv(3) manual page being referenced from ares_set_servers(3) is missing in Debian. I believe it is present upstream, <URL: https://github.com/bagder/c-ares/blob/master/ares_set_servers_csv.3 >.
Please provide it in the Debian package too. -- Happy hacking Petter Reinholdtsen