Minimum CMake version

[mwestphal (Mathieu Westphal (Kitware))]

Didn’t we see someone running cmake 3.9 here :

9.0.0.rc1 CMake policy error (using CMake 3.9.3)

Linux, rhel7, CMake 3.9.3, I passed no args to CMake, and configure fails with this error: CMake Error at ThirdParty/hdf5/CMakeLists.txt:2 (cmake_policy): Policy “CMP0074” is not known to this version of CMake.

Rhel7.