extern uschar *dns_ipv4_lookup; /* For these domains, don't look for AAAA (or A6) */
extern int dns_retrans; /* Retransmission time setting */
extern int dns_retry; /* Number of retries */
+extern int dns_use_edns0; /* Coerce EDNS0 support on/off in resolver. */
extern uschar *dnslist_domain; /* DNS (black) list domain */
extern uschar *dnslist_matched; /* DNS (black) list matched key */
extern uschar *dnslist_text; /* DNS (black) list text message */