diff --git a/src/modules/files/file_machine.h.in b/src/modules/files/file_machine.h.in
index ed7b4a983817db2afe2722621a8d43d62ff1482f..fcbcdc862913532d9c04dde8e14870d7687dd24f 100644
--- a/src/modules/files/file_machine.h.in
+++ b/src/modules/files/file_machine.h.in
@@ -43,9 +43,18 @@
 /* Define if you have fork1.  */
 #undef HAVE_FORK1
 
-/* Define if you have a solaris compatible readdir_r.  */
+/* Define if you have readdir_r.  */
 #undef HAVE_READDIR_R
 
+/* Define if your readdir_r is POSIX compatible. */
+#undef HAVE_POSIX_READDIR_R
+
+/* Define if your readdir_r is Solaris compatible. */
+#undef HAVE_SOLARIS_READDIR_R
+
+/* Define if your readdir_r is HPUX compatible. */
+#undef HAVE_HPUX_READDIR_R
+
 /* Define if you have strerror.  */
 #undef HAVE_STRERROR