--- /dev/null
+diff -ur postfix-3.4.6.orig/src/dns/dns_str_resflags.c postfix-3.4.6/src/dns/dns_str_resflags.c
+--- postfix-3.4.6.orig/src/dns/dns_str_resflags.c 2016-05-15 17:20:14.000000000 +0200
++++ postfix-3.4.6/src/dns/dns_str_resflags.c 2019-09-05 22:01:00.522000000 +0200
+@@ -60,10 +60,16 @@
+ "RES_DEFNAMES", RES_DEFNAMES,
+ "RES_STAYOPEN", RES_STAYOPEN,
+ "RES_DNSRCH", RES_DNSRCH,
++#ifdef RES_INSECURE1
+ "RES_INSECURE1", RES_INSECURE1,
++#endif
++#ifdef RES_INSECURE2
+ "RES_INSECURE2", RES_INSECURE2,
++#endif
+ "RES_NOALIASES", RES_NOALIASES,
++#ifdef RES_USE_INET6
+ "RES_USE_INET6", RES_USE_INET6,
++#endif
+ #ifdef RES_ROTATE
+ "RES_ROTATE", RES_ROTATE,
+ #endif