fix glGet with matrix stack depth
fix glGet with matrix stack depth

seandepagnier/glshim,RobertoMalatesta/glshim,RobertoMalatesta/glshim,lunixbochs/glshim,RobertoMalatesta/glshim,seandepagnier/glshim,lunixbochs/glshim,seandepagnier/glshim,lunixbochs/glshim,RobertoMalatesta/glshim,lunixbochs/glshim,seandepagnier/glshim