Diff of /src/qtgui/preview_w.h [631fad] .. [64a2c4]

  Switch to side-by-side view 

--- a/src/qtgui/preview_w.h
+++ b/src/qtgui/preview_w.h
@@ -20,6 +20,7 @@
 
 #include <qvariant.h>
 #include <qwidget.h>
+#include <stdio.h>
 
 #include "rcldb.h"
 #include "refcntr.h"