Better solution for spurious out of memory error in glMapBuffer.
Better solution for spurious out of memory error in glMapBuffer.

svn path=/trunk/libavg/; revision=1879

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