diff --git a/libweston/compositor.c b/libweston/compositor.c
index c8bcbb08..0c6d1eb9 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -66,6 +66,9 @@
 
 #define DEFAULT_REPAINT_WINDOW 7 /* milliseconds */
 
+static void
+weston_output_update_matrix(struct weston_output *output);
+
 static void
 weston_output_transform_scale_init(struct weston_output *output,
 				   uint32_t transform, uint32_t scale);
@@ -4344,7 +4347,7 @@ weston_compositor_reflow_outputs(struct weston_compositor *compositor,
 	}
 }
 
-WL_EXPORT void
+static void
 weston_output_update_matrix(struct weston_output *output)
 {
 	float magnification;
diff --git a/libweston/compositor.h b/libweston/compositor.h
index e90bfe84..4e01f056 100644
--- a/libweston/compositor.h
+++ b/libweston/compositor.h
@@ -1714,8 +1714,6 @@ void
 weston_output_activate_zoom(struct weston_output *output,
 			    struct weston_seat *seat);
 void
-weston_output_update_matrix(struct weston_output *output);
-void
 weston_output_move(struct weston_output *output, int x, int y);
 
 void