diff --git a/libs/ardour/ardour/audio_unit.h b/libs/ardour/ardour/audio_unit.h
index 07f41f5526..8233e208d3 100644
--- a/libs/ardour/ardour/audio_unit.h
+++ b/libs/ardour/ardour/audio_unit.h
@@ -41,7 +41,7 @@
 class CAComponent;
 class CAAudioUnit;
 class CAComponentDescription;
-struct LIBARDOUR_API AudioBufferList;
+struct AudioBufferList;
 
 namespace ARDOUR {