Fix build on Windows with new qdatetime.h that doesn't redefine min/max

Windows system header files redefine min/max, unless NOMINMAX is defined.
In some cases we can simply include qt_windows.h, which does the trick,
in other cases including qt_windows.h produces different compilation
errors and it's simpler to just do the NOMINMAX trick.

Change-Id: I3cf81bab7c239363adfa274f158bdf999d1d3ecd
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/multimedia/audio/qaudioinput_win32_p.h

@@ -53,6 +53,8 @@
 #ifndef QAUDIOINPUTWIN_H
 #define QAUDIOINPUTWIN_H
 
+#define NOMINMAX
+
 #include <windows.h>
 #include <mmsystem.h>
 

src/multimedia/audio/qaudiooutput_win32_p.h

@@ -53,6 +53,8 @@
 #ifndef QAUDIOOUTPUTWIN_H
 #define QAUDIOOUTPUTWIN_H
 
+#define NOMINMAX
+
 #include <windows.h>
 #include <mmsystem.h>
 

src/plugins/directshow/player/directshoweventloop.h

@@ -46,7 +46,7 @@
 #include <QtCore/qobject.h>
 #include <QtCore/qwaitcondition.h>
 
-#include <windows.h>
+#include <qt_windows.h>
 
 class DirectShowPostedEvent;