Add snippet for QT_VERSION_CHECK.

Change-Id: I048771f21ce694329a7e9acd4dbfbebfec964b05
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/doc/snippets/code/src_corelib_global_qglobal.cpp

@@ -598,3 +598,13 @@ bool readConfiguration(const QFile &file)
            break;
    }
 //! [qunreachable-switch]
+
+//! [qt-version-check]
+#include <QtGlobal>
+
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 0, 0))
+#include <QtWidgets>
+#else
+#include <QtGui>
+#endif
+//! [qt-version-check]

src/corelib/global/qglobal.cpp

@@ -846,6 +846,10 @@ Q_CORE_EXPORT void *qMemSet(void *dest, int c, size_t n);
     integer, 0xMMNNPP (MM = major, NN = minor, PP = patch). This can
     be compared with another similarly processed version id.
 
+    Example:
+
+    \snippet code/src_corelib_global_qglobal.cpp qt-version-check
+
     \sa QT_VERSION
 */