diff --git a/configure.ac b/configure.ac
index 51bc8bd..92c831a 100755
--- a/configure.ac
+++ b/configure.ac
@@ -472,6 +472,9 @@
 #if HAVE_SYS_SOCKET_H
 # include <sys/socket.h>
 #endif
+#ifdef __APPLE__
+# define __APPLE_USE_RFC_3542
+#endif
 #if HAVE_NETINET_IN_H
 # include <netinet/in.h>
 #endif