diff --git a/include/dix-config.h.in b/include/dix-config.h.in
index 4c3a4b7a0..2b9f273d7 100644
--- a/include/dix-config.h.in
+++ b/include/dix-config.h.in
@@ -231,6 +231,9 @@
 /* Disable some debugging code */
 #undef NDEBUG
 
+/* Enable some debugging code */
+#undef DEBUG
+
 /* Name of package */
 #undef PACKAGE