Further fixes for disabling pthreads and win32 threads on mingw.
Further fixes for disabling pthreads and win32 threads on mingw.

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