diff --git a/libs/ardour/wscript b/libs/ardour/wscript
index 1665816792..49cea6abbd 100644
--- a/libs/ardour/wscript
+++ b/libs/ardour/wscript
@@ -173,6 +173,7 @@ libardour_sources = [
         'plugin_manager.cc',
         'polarity_processor.cc',
         'port.cc',
+        'port_engine_shared.cc',
         'port_insert.cc',
         'port_manager.cc',
         'port_set.cc',