diff --git a/bin/dig/nslookup.c b/bin/dig/nslookup.c
index 08ee5e36d9..7309c8cdbf 100644
--- a/bin/dig/nslookup.c
+++ b/bin/dig/nslookup.c
@@ -47,6 +47,11 @@
 #elif defined(HAVE_EDITLINE_READLINE_H)
 #include <editline/readline.h>
 #elif defined(HAVE_READLINE_READLINE_H)
+/* Prevent deprecated functions being declared. */
+#define _FUNCTION_DEF 1
+/* Ensure rl_message() gets prototype. */
+#define USE_VARARGS   1
+#define PREFER_STDARG 1
 #include <readline/readline.h>
 #if defined(HAVE_READLINE_HISTORY_H)
 #include <readline/history.h>
diff --git a/bin/nsupdate/nsupdate.c b/bin/nsupdate/nsupdate.c
index b7fc15fbc8..654c6508d8 100644
--- a/bin/nsupdate/nsupdate.c
+++ b/bin/nsupdate/nsupdate.c
@@ -103,6 +103,11 @@
 #elif defined(HAVE_EDITLINE_READLINE_H)
 #include <editline/readline.h>
 #else /* if defined(HAVE_EDIT_READLINE_READLINE_H) */
+/* Prevent deprecated functions being declared. */
+#define _FUNCTION_DEF 1
+/* Ensure rl_message() gets prototype. */
+#define USE_VARARGS   1
+#define PREFER_STDARG 1
 #include <readline/history.h>
 #include <readline/readline.h>
 #endif /* if defined(HAVE_EDIT_READLINE_READLINE_H) */