Fix build of QGestureRecognizer on OS X

ifdef panTouchPoints which is not used on OS X. Otherwise the build
fails when the -Werror,-Wunused-function flags are used.

Change-Id: I4f5498774905fcb2ba1fae40e41587d5821af8b9
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>

src/widgets/kernel/qgesturemanager.cpp

@@ -63,6 +63,7 @@
 
 QT_BEGIN_NAMESPACE
 
+#if !defined(Q_OS_OSX)
 static inline int panTouchPoints()
 {
     // Override by environment variable for testing.
@@ -80,6 +81,7 @@ static inline int panTouchPoints()
     // correctly.
     return 2;
 }
+#endif
 
 QGestureManager::QGestureManager(QObject *parent)
     : QObject(parent), state(NotGesture), m_lastCustomGestureId(Qt::CustomGesture)