fix compilation with conforming compilers (e.g. GCC >= 4.7)

In qdbus_cast(), qMetaTypeId<QDBusArgument> as well as
qvariant_cast<QDBusArgument> are used. They don't depend
on any template argument of qdbus_cast(), so their
definitions need to be available at function template
definition instead of instantiation time.

But the necessary Q_DECLARE_METATYPE(QDBusArgument)
was at the end of the header, after the defintion of
qdbus_cast(), which is too late for conformin compilers.

Fixed by moving it up just after the QDBusArgument
definition.

Similarly, in tst_qdatetime and tst_qvector, the
Q_DECLARE_METATYPE() for Qt::DateFormat and QVector<int>,
and with it the specialisation of QMetaTypeId<>, were
issued after the first use of meta typing; too late for
conforming compilers.

Change-Id: I25ca0b06e68d5184597a22708404a8f2040b2de1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/dbus/qdbusargument.h

@@ -151,6 +151,10 @@ protected:
     mutable QDBusArgumentPrivate *d;
 };
 
+QT_END_NAMESPACE
+Q_DECLARE_METATYPE(QDBusArgument)
+QT_BEGIN_NAMESPACE
+
 template<typename T> inline T qdbus_cast(const QDBusArgument &arg
 #ifndef Q_QDOC
 , T * = 0
@@ -396,8 +400,6 @@ inline QDBusArgument &operator<<(QDBusArgument &arg, const QVariantHash &map)
 
 QT_END_NAMESPACE
 
-Q_DECLARE_METATYPE(QDBusArgument)
-
 QT_END_HEADER
 
 #endif // QT_NO_DBUS

tests/auto/corelib/tools/qdatetime/tst_qdatetime.cpp

@@ -141,6 +141,7 @@ Q_DECLARE_METATYPE(QDateTime)
 Q_DECLARE_METATYPE(QDate)
 Q_DECLARE_METATYPE(QTime)
 Q_DECLARE_METATYPE(Qt::TimeSpec)
+Q_DECLARE_METATYPE(Qt::DateFormat)
 
 tst_QDateTime::tst_QDateTime()
 {
@@ -1626,7 +1627,5 @@ void tst_QDateTime::utcOffsetLessThan() const
     QVERIFY(!(dt2 < dt1));
 }
 
-Q_DECLARE_METATYPE(Qt::DateFormat)
-
 QTEST_APPLESS_MAIN(tst_QDateTime)
 #include "tst_qdatetime.moc"

tests/auto/corelib/tools/qvector/tst_qvector.cpp

@@ -293,6 +293,8 @@ private:
     template<typename T> void detach() const;
 };
 
+Q_DECLARE_METATYPE(QVector<int>);
+
 template<typename T> struct SimpleValue
 {
     static T at(int index)
@@ -2026,8 +2028,6 @@ void tst_QVector::const_shared_null()
     QVERIFY(!v2.isDetached());
 }
 
-Q_DECLARE_METATYPE(QVector<int>);
-
 template<typename T>
 void tst_QVector::setSharable_data() const
 {