$NetBSD: patch-configure,v 1.5 2023/06/02 15:57:57 schmonz Exp $

Test for res_close, not available in OpenBSD.

--- configure.orig	2021-06-09 05:43:12.000000000 +0000
+++ configure
@@ -13494,6 +13494,33 @@ cat >>confdefs.h <<_ACEOF
 #define HAVE_DECL_RES_NDESTROY $ac_have_decl
 _ACEOF
 
+ac_fn_c_check_decl "$LINENO" "res_close" "ac_cv_have_decl_res_close" "
+	#ifdef HAVE_SYS_TYPES_H
+	# include <sys/types.h>
+	#endif
+	#ifdef HAVE_SYS_SOCKET_H
+	# include <sys/socket.h>		/* inet_ functions / structs */
+	#endif
+	#ifdef HAVE_NETINET_IN_H
+	# include <netinet/in.h>		/* inet_ functions / structs */
+	#endif
+	#ifdef HAVE_ARPA_NAMESER_H
+	#  include <arpa/nameser.h> /* DNS HEADER struct */
+	#endif
+	#ifdef HAVE_RESOLV_H
+	# include <resolv.h>
+	#endif
+
+"
+if test "x$ac_cv_have_decl_res_close" = xyes; then :
+  ac_have_decl=1
+else
+  ac_have_decl=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_RES_CLOSE $ac_have_decl
+_ACEOF
 
 ac_fn_c_check_decl "$LINENO" "ns_t_spf" "ac_cv_have_decl_ns_t_spf" "
 	#ifdef HAVE_SYS_TYPES_H