diff --git a/libs/surfaces/osc/osc_gui.cc b/libs/surfaces/osc/osc_gui.cc
index 72f15a6d96..68501693b2 100644
--- a/libs/surfaces/osc/osc_gui.cc
+++ b/libs/surfaces/osc/osc_gui.cc
@@ -24,6 +24,8 @@
 #include <vector>
 //#include <glibmm/miscutils.h>
 
+#include <errno.h>
+
 #include "pbd/file_utils.h"
 
 #include <gtkmm/box.h>