diff --git a/include/portable.h.in b/include/portable.h.in
index c604dfe499..807a57e89d 100644
--- a/include/portable.h.in
+++ b/include/portable.h.in
@@ -992,6 +992,9 @@
 /* define for Dynamic Group overlay */
 #undef SLAPD_OVER_DYNGROUP
 
+/* define for Last Modification overlay */
+#undef SLAPD_OVER_LASTMOD
+
 /* define for Password Policy overlay */
 #undef SLAPD_OVER_PPOLICY