extern int dns_lookup(dns_answer *, uschar *, int, uschar **);
extern int dns_special_lookup(dns_answer *, uschar *, int, uschar **);
extern dns_record *dns_next_rr(dns_answer *, dns_scan *, int);
extern int dns_lookup(dns_answer *, uschar *, int, uschar **);
extern int dns_special_lookup(dns_answer *, uschar *, int, uschar **);
extern dns_record *dns_next_rr(dns_answer *, dns_scan *, int);