diff --git a/libs/ardour/control_protocol_manager.cc b/libs/ardour/control_protocol_manager.cc
index f10b58f608..b316abc0f6 100644
--- a/libs/ardour/control_protocol_manager.cc
+++ b/libs/ardour/control_protocol_manager.cc
@@ -22,6 +22,8 @@
  */
 
 #ifdef HAVE_USB
+#include "pbd/pthread_utils.h"
+
 #include <libusb.h>
 /* ControlProtocolManager is a singleton, so we can use static
  * here. This has the advantage that libusb.h does not need