diff --git a/config.h.in b/config.h.in
index 82d64b8ae..5ef404379 100644
--- a/config.h.in
+++ b/config.h.in
@@ -333,6 +333,12 @@
 /* Define to 1 if you have the <paths.h> header file. */
 #undef HAVE_PATHS_H
 
+/* Define to 1 if you have the `posix_openpt' function. */
+#undef HAVE_POSIX_OPENPT
+
+/* Define to 1 if you have the `grantpt' function. */
+#undef HAVE_GRANTPT
+
 /* Define to 1 if you have the <project.h> header file. */
 #undef HAVE_PROJECT_H