Define Q_NULLPTR as NULL if not already defined

it is not supported with Qt 4.x

Change-Id: Ie98d5e03d471869e08f5354a509c3317c7c780d7
Reviewed-on: https://code.wireshark.org/review/22831
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

ui/qt/utils/qt_ui_utils.h

@@ -54,6 +54,11 @@ struct epan_range;
 }
 #endif /* __cplusplus */
 
+// Needed to support Qt 4.x
+#ifndef Q_NULLPTR
+#define Q_NULLPTR NULL
+#endif
+
 /** Create a glib-compatible copy of a QString.
  *
  * @param q_string A QString.

ui/qt/widgets/drag_drop_toolbar.h

@@ -24,6 +24,7 @@
 
 #include <QToolBar>
 #include <QPoint>
+#include <ui/qt/utils/qt_ui_utils.h>
 
 class DragDropToolBar : public QToolBar
 {