Fix GLSL scale bias shader on OSX.
Fix GLSL scale bias shader on OSX.

stevenlovegrove/Pangolin,visigoth/Pangolin,renzodenardi/Pangolin,randi120/Pangolin,arpg/Pangolin,wxdzju/Pangolin,mp3guy/Pangolin,tschmidt23/Pangolin,mp3guy/Pangolin,arpg/Pangolin,pinglin/Pangolin,pinglin/Pangolin,visigoth/Pangolin,tschmidt23/Pangolin,renzodenardi/Pangolin,wxdzju/Pangolin,stevenlovegrove/Pangolin,mp3guy/Pangolin,tschmidt23/Pangolin,randi120/Pangolin,stevenlovegrove/Pangolin