$OpenBSD$

Index: src/mongo/util/dns_query_posix-impl.h
--- src/mongo/util/dns_query_posix-impl.h.orig
+++ src/mongo/util/dns_query_posix-impl.h
@@ -39,6 +39,16 @@
 #include <resolv.h>
 // clang-format on
 
+#define ns_c_in C_IN
+#define ns_t_srv T_SRV
+#define ns_t_txt T_TXT
+#define ns_t_a T_A
+#ifndef res_ninit
+#define res_nclose(arg)
+#define res_ninit(arg)    res_init()
+#define res_nsearch(sta, nam, clas, typ, ans, alen)  res_search(nam, clas, typ, ans, alen)
+#endif
+
 #include <stdio.h>
 
 #include <iostream>