diff --git a/appl/popper/popper.h b/appl/popper/popper.h
index 4d6b85659..702db2fdf 100644
--- a/appl/popper/popper.h
+++ b/appl/popper/popper.h
@@ -17,6 +17,7 @@
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #include <protos.h>
+#define UIDL
 #define DEBUG
 #define RETURN_PATH_HANDLING
 #endif