Allow vtkm_find_gl CMake function to be used no matter vtk-m settings
Previously vtkm_find_gl was only usable when rendering was enabled. This is problematic as examples would use vtkm_find_gl even if they didn't use vtkm rendering library.
Previously vtkm_find_gl was only usable when rendering was enabled. This is problematic as examples would use vtkm_find_gl even if they didn't use vtkm rendering library.