iso2mesh uses ancient CMake declarations like
cmake_minimum_required(VERSION 2.6.2)
whereas CGAL requires at least CMake-3.4, and recently 3.14.
In particular, that triggers a hard error because of
`CMP0064` (introduced by CMake-3.4).
See also the upstream PR https://github.com/CGAL/cgal/pull/5859 for
another workaround.