cholmod support links parmetis when parmetis support is disabled.
Issue #928
new
When cholmod support is activated in dolfin, it links to parmetis even if parmetis support is disabled (when DOLFIN_ENABLE_PARMETIS=OFF)
This happens because cmake/modules/FindCHOLMOD.cmake includes "find_package(ParMETIS 4.0.2 QUIET)"
It would be more internally consistent for cholmod to not pull in parmetis, if DOLFIN_ENABLE_PARMETIS=OFF.
The context in Debian is that dolfin is placed in Debian main, which excludes non-free packages. parmetis is a non-free package (freely available for non-commercial use but not licensed for commercial applications). So Debian explicitly uses DOLFIN_ENABLE_PARMETIS=OFF
A simple patch is to test the value of DOLFIN_ENABLE_PARMETIS in FindCHOLMOD.cmake. We've made the attached simple patch for Debian.
