work around MSVC level 4 warning

Change-Id: Ide3541a8a1a16a1f9b6b01f54d5b2f6ab178c3ac
Task-number: QTBUG-7233
Reviewed-by: hjk <hjk@theqtcompany.com>

src/corelib/global/qglobal.h

@@ -865,6 +865,7 @@ Q_CORE_EXPORT void qFreeAligned(void *ptr);
 /* make use of decltype or GCC's __typeof__ extension */
 template <typename T>
 class QForeachContainer {
+    QForeachContainer &operator=(const QForeachContainer &) Q_DECL_EQ_DELETE;
 public:
     inline QForeachContainer(const T& t) : c(t), i(c.begin()), e(c.end()), control(1) { }
     const T c;