-#ifndef HAVE_GETHOSTBYADDR_R
-extern pthread_mutex_t gethostbyaddr_mutex;
-#endif /* ndef HAVE_GETHOSTBYADDR_R */
-
-#ifndef HAVE_GETHOSTBYNAME_R
-extern pthread_mutex_t gethostbyname_mutex;
-#endif /* ndef HAVE_GETHOSTBYNAME_R */
+#if !defined(HAVE_GETHOSTBYADDR_R) || !defined(HAVE_GETHOSTBYNAME_R)
+extern pthread_mutex_t resolver_mutex;
+#endif /* !defined(HAVE_GETHOSTBYADDR_R) || !defined(HAVE_GETHOSTBYNAME_R) */