[Interest] Maybe a problem with the include <QtOpenGL/QGLContext> on windows

[arnaud but]

Hello everybody,

during my work on phonon, i remark that include <QtOpenGL/QGLContext> 
does not reference opengl on windows plattform(msvc2010) (it seems good 
on linux and mac).

in the order :

#include <QtOpenGL/QGLContext> that include :

#include "qgl.h" : into this file
----------------
#if defined(Q_WS_WIN)
# include <QtCore/qt_windows.h>
#endif

#if defined(Q_WS_MAC)
# include <OpenGL/gl.h>
#elif defined(QT_OPENGL_ES_1)
# if defined(Q_OS_MAC)
#  include <OpenGLES/ES1/gl.h>
# else
#  include <GLES/gl.h>
# endif
----------------------
so on windows it uses qt_windows.h.
qt_windows.h include windows.h but in this one there is no reference to 
gl.h.

i think we must add into qgl.h :

#if defined(Q_WS_WIN)
# include <QtCore/qt_windows.h>
#include <Gl/gl.h>
#endif

what do you think about that ?