Fix screenshot function under GLES/EGl
Fix screenshot function under GLES/EGl

Fixes most tests

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