Drop the unbound dependency in libdane
That dependency requires linking to either openssl or nss; and both are unacceptable for several distributors (e.g., Debian). The current plan is to convert libdane to a non-validating dnssec library that depends on a validating server running on localhost - e.g., unbound or dnsmasq. Such library currently does not exist, but there is patch for c-ares.