diff --git a/libs/surfaces/push2/push2.cc b/libs/surfaces/push2/push2.cc
index 484dbcccdb..03e0175a91 100644
--- a/libs/surfaces/push2/push2.cc
+++ b/libs/surfaces/push2/push2.cc
@@ -17,6 +17,7 @@
 */
 
 #include <stdlib.h>
+#include <pthread.h>
 
 #include "pbd/compose.h"
 #include "pbd/convert.h"