Undef interface in more places, fixing builds with libc++ on windows

After including windows.h, interface is a define that expands to
"struct" (unless WIN32_LEAN_AND_MEAN is defined). This name is
used as a normal identifier in multiple places within Qt.

This has already been worked around in a number of places
(in e.g. 3ba61d9baa and
786d23bb49).

After qrandom.h was included in <QtCore/QtCore>, this header
implicitly includes <random>. In libc++ on windows, this header
then transitively includes windows.h, exposing the clash with
the name "interface" in even more locations than before.

For cases within qtbase internals, it could also alternatively be
handled by defining WIN32_LEAN_AND_MEAN while building QtDbus, but
for occurrences in public headers, the undef trick needs to be
used.

Change-Id: I89754f38f55ae7f2145255a2c8a71b23492be6a1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/thread/qfutureinterface.cpp

@@ -48,6 +48,10 @@
 #include <QtCore/qthread.h>
 #include <private/qthreadpool_p.h>
 
+#ifdef interface
+#  undef interface
+#endif
+
 QT_BEGIN_NAMESPACE
 
 enum {

src/dbus/qdbus_symbols_p.h

@@ -63,6 +63,10 @@
 #  include "dbus_minimal_p.h"
 #endif
 
+#ifdef interface
+#  undef interface
+#endif
+
 QT_BEGIN_NAMESPACE
 
 #if !defined QT_LINKED_LIBDBUS

src/dbus/qdbusabstractadaptor_p.h

@@ -67,6 +67,10 @@
 
 #ifndef QT_NO_DBUS
 
+#ifdef interface
+#  undef interface
+#endif
+
 QT_BEGIN_NAMESPACE
 
 class QDBusAbstractAdaptor;

src/dbus/qdbusconnection.h

@@ -47,6 +47,10 @@
 
 #ifndef QT_NO_DBUS
 
+#ifdef interface
+#  undef interface
+#endif
+
 QT_BEGIN_NAMESPACE
 
 

src/dbus/qdbusmetaobject_p.h

@@ -57,6 +57,10 @@
 
 #ifndef QT_NO_DBUS
 
+#ifdef interface
+#  undef interface
+#endif
+
 QT_BEGIN_NAMESPACE
 
 class QDBusError;