QFutureCallOutEvent: de-export again

A previous commit Q_CORE_EXPORTed this class so it could be used in
tst_qevent. But we can also keep it Q_AUTOTEST_EXPORTed and make the
testing of the class subject to QT_BUILD_INTERNAL on the test side.

That's what this patch does.

Change-Id: I9bd5f80ada856b7db4b39dfb59b32bd825416c13
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

src/corelib/thread/qfutureinterface_p.h

@@ -65,7 +65,7 @@ QT_REQUIRE_CONFIG(future);
 
 QT_BEGIN_NAMESPACE
 
-class Q_CORE_EXPORT QFutureCallOutEvent : public QEvent
+class Q_AUTOTEST_EXPORT QFutureCallOutEvent : public QEvent
 {
     Q_DECL_EVENT_COMMON(QFutureCallOutEvent)
 public:

tests/auto/gui/kernel/qevent/tst_qevent.cpp

@@ -33,6 +33,12 @@
 #include <QtGui/qevent.h>
 #include <QtCore/private/qfutureinterface_p.h>
 
+#ifdef QT_BUILD_INTERNAL
+# define ONLY_IF_INTERNAL_BUILD(...) __VA_ARGS__
+#else
+# define ONLY_IF_INTERNAL_BUILD(...)
+#endif
+
 #define FOR_EACH_CORE_EVENT(X) \
     /* qcoreevent.h */ \
     X(QEvent, (QEvent::None)) \
@@ -41,7 +47,7 @@
     X(QDynamicPropertyChangeEvent, ("size")) \
     X(QDeferredDeleteEvent, ()) \
     /* qfutureinterface_p.h */ \
-    X(QFutureCallOutEvent, ()) \
+    ONLY_IF_INTERNAL_BUILD(X(QFutureCallOutEvent, ())) \
     /* end */
 
 #define FOR_EACH_GUI_EVENT(X) \