multisample context creation: Windows version.
multisample context creation: Windows version.

svn path=/trunk/libavg/; revision=9537

libavg/libavg,th3infinity/libavg,libavg/libavg,yyd01245/libavg,scotty007/libavg,yyd01245/libavg,scotty007/libavg,hoodie/libavg,scotty007/libavg,th3infinity/libavg,hoodie/libavg,th3infinity/libavg,scotty007/libavg,yyd01245/libavg,libavg/libavg,th3infinity/libavg,hoodie/libavg,libavg/libavg,yyd01245/libavg,hoodie/libavg