Handle "-psn_XXX" command line args on Mac

Finder on Mac OS X sends a command line argument of
the form -psn_0_3523420 when launching applications.
Eat the argument like we do in Qt 4.

Change-Id: I09db9dea035e62c0b816a833c9ad6fcd78f83735
Reviewed-by: Teemu Katajisto <teemu.katajisto@digia.com>
Reviewed-by: Simo Fält <simo.falt@nokia.com>
Reviewed-by: Marius Storm-Olsen <marius.storm-olsen@nokia.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

src/gui/kernel/qguiapplication.cpp

@@ -842,6 +842,10 @@ void QGuiApplicationPrivate::init()
         } else if (arg == "-reverse") {
             force_reverse = true;
             QGuiApplication::setLayoutDirection(Qt::RightToLeft);
+#ifdef Q_OS_MAC
+        } else if (arg.startsWith("-psn_")) {
+            // eat "-psn_xxxx" on Mac
+#endif
         } else {
             argv[j++] = argv[i];
         }