dirmngr: Prefer ADNS over system resolver.
* configure.ac (HAVE_ADNS_IF_TORMODE): New ac_define. (USE_DNS_CERT): Prefer ADNS over the system resolver. * dirmngr/dns-cert.c (tor_mode): New global var. (enable_dns_tormode): New func. (get_dns_cert): Use DNS resolver at 8.8.8.8 in tor-mode. * dirmngr/server.c (cmd_dns_cert): If supported allow DNS requests.