BUG: Fix compilation error when (windows) doesn't know what GL_MULTISAMPLE is.
BUG: Fix compilation error when (windows) doesn't know what GL_MULTISAMPLE is.

arnaudgelas/VTK,candy7393/VTK,candy7393/VTK,biddisco/VTK,gram526/VTK,spthaolt/VTK,johnkit/vtk-dev,ashray/VTK-EVM,spthaolt/VTK,berendkleinhaneveld/VTK,naucoin/VTKSlicerWidgets,cjh1/VTK,berendkleinhaneveld/VTK,jeffbaumes/jeffbaumes-vtk,hendradarwin/VTK,johnkit/vtk-dev,cjh1/VTK,sumedhasingla/VTK,jeffbaumes/jeffbaumes-vtk,msmolens/VTK,demarle/VTK,sankhesh/VTK,jmerkow/VTK,aashish24/VTK-old,Wuteyan/VTK,jmerkow/VTK,Wuteyan/VTK,sumedhasingla/VTK,daviddoria/PointGraphsPhase1,mspark93/VTK,sankhesh/VTK,demarle/VTK,jmerkow/VTK,cjh1/VTK,aashish24/VTK-old,daviddoria/PointGraphsPhase1,sankhesh/VTK,biddisco/VTK,Wuteyan/VTK,keithroe/vtkoptix,SimVascular/VTK,sumedhasingla/VTK,spthaolt/VTK,mspark93/VTK,demarle/VTK,keithroe/vtkoptix,demarle/VTK,daviddoria/PointGraphsPhase1,ashray/VTK-EVM,ashray/VTK-EVM,aashish24/VTK-old,candy7393/VTK,arnaudgelas/VTK,ashray/VTK-EVM,msmolens/VTK,aashish24/VTK-old,Wuteyan/VTK,ashray/VTK-EVM,sumedhasingla/VTK,sankhesh/VTK,mspark93/VTK,collects/VTK,berendkleinhaneveld/VTK,keithroe/vtkoptix,berendkleinhaneveld/VTK,biddisco/VTK,keithroe/vtkoptix,demarle/VTK,johnkit/vtk-dev,naucoin/VTKSlicerWidgets,jeffbaumes/jeffbaumes-vtk,hendradarwin/VTK,collects/VTK,arnaudgelas/VTK,mspark93/VTK,sumedhasingla/VTK,jeffbaumes/jeffbaumes-vtk,SimVascular/VTK,demarle/VTK,spthaolt/VTK,sumedhasingla/VTK,SimVascular/VTK,SimVascular/VTK,aashish24/VTK-old,jeffbaumes/jeffbaumes-vtk,gram526/VTK,gram526/VTK,cjh1/VTK,keithroe/vtkoptix,berendkleinhaneveld/VTK,sumedhasingla/VTK,collects/VTK,SimVascular/VTK,johnkit/vtk-dev,demarle/VTK,demarle/VTK,gram526/VTK,biddisco/VTK,johnkit/vtk-dev,Wuteyan/VTK,candy7393/VTK,SimVascular/VTK,biddisco/VTK,ashray/VTK-EVM,naucoin/VTKSlicerWidgets,candy7393/VTK,keithroe/vtkoptix,jmerkow/VTK,Wuteyan/VTK,hendradarwin/VTK,sumedhasingla/VTK,collects/VTK,daviddoria/PointGraphsPhase1,naucoin/VTKSlicerWidgets,msmolens/VTK,ashray/VTK-EVM,spthaolt/VTK,jeffbaumes/jeffbaumes-vtk,hendradarwin/VTK,spthaolt/VTK,mspark93/VTK,jmerkow/VTK,keithroe/vtkoptix,spthaolt/VTK,berendkleinhaneveld/VTK,sankhesh/VTK,arnaudgelas/VTK,SimVascular/VTK,hendradarwin/VTK,jmerkow/VTK,cjh1/VTK,daviddoria/PointGraphsPhase1,jmerkow/VTK,keithroe/vtkoptix,gram526/VTK,hendradarwin/VTK,berendkleinhaneveld/VTK,candy7393/VTK,naucoin/VTKSlicerWidgets,gram526/VTK,biddisco/VTK,jmerkow/VTK,sankhesh/VTK,sankhesh/VTK,candy7393/VTK,Wuteyan/VTK,msmolens/VTK,msmolens/VTK,SimVascular/VTK,candy7393/VTK,aashish24/VTK-old,daviddoria/PointGraphsPhase1,hendradarwin/VTK,msmolens/VTK,johnkit/vtk-dev,arnaudgelas/VTK,gram526/VTK,naucoin/VTKSlicerWidgets,collects/VTK,sankhesh/VTK,mspark93/VTK,gram526/VTK,collects/VTK,mspark93/VTK,johnkit/vtk-dev,ashray/VTK-EVM,cjh1/VTK,biddisco/VTK,arnaudgelas/VTK,msmolens/VTK,msmolens/VTK,mspark93/VTK