Cleanup/correct workaround for old OS X 10.6 bug (!1373) · Merge requests · VTK / VTK · GitLab

Sean McBride requested to merge seanm/vtk:clean-old-OSX10.6-workaround into master Mar 24, 2016

correct backwards logic recently introduced by 56a17faf, the workaround was being applied to non-nVidia instead of for nVidia!
removed test code, as no one will be debugging ancient 10.6 bugs anymore.
replaced fragile version string tests, instead check host OS version