diff --git a/acconfig.h b/acconfig.h
index 483fd36a7..507f7f64f 100644
--- a/acconfig.h
+++ b/acconfig.h
@@ -43,7 +43,7 @@
 #undef HAVE_UT_SYSLEN
 
 /*  Define this if you have a struct sockaddr_in6 */
-#undef HAVE_SOCKADDR_IN6
+#undef HAVE_STRUCT_SOCKADDR_IN6
 
 /* define if you have h_errno */
 #undef HAVE_H_ERRNO