diff --git a/src/modules/module-rtkit.c b/src/modules/module-rtkit.c
index 483cf1277..894b3501d 100644
--- a/src/modules/module-rtkit.c
+++ b/src/modules/module-rtkit.c
@@ -105,6 +105,10 @@ struct impl {
 #define RTKIT_SERVICE_NAME "org.freedesktop.RealtimeKit1"
 #define RTKIT_OBJECT_PATH "/org/freedesktop/RealtimeKit1"
 
+#ifndef RLIMIT_RTTIME
+#define RLIMIT_RTTIME 15
+#endif
+
 /** \cond */
 struct pw_rtkit_bus {
 	DBusConnection *bus;