VERSION support for FindGL2PS.cmake required
ThirdParty/gl2ps/CMakeLists.txt requests (via vtk_module_third_party in CMake/vtkModuleMacros.cmake) VERSION >=1.4.0 of GL2PS. However, CMake/FindGL2PS.cmake does not support version tests.
Thus the intention of 1520938b, to make sure the system supplied GL2PS is sufficient to compile VTK, is not actually respected and "outdated" installations of GL2PS will not be detected (VTK's version requirement will be ignored).
I discovered this issue during my attempts to compile ParaView 5.2.0, which uses commit 6cf5847e of VTK, authored about two weeks before version 7.1.0 was released.
See-Also: issue #16083 (closed)