GenProg 4.0 is OCaml 4.12.0-compliant (or rather, builds after 4.05, which was untrue of the previous version). Build instructions in README; requires a fork of Cil. Code is otherwise only lightly modified to bring it up to date with modern OCaml API. However, since those changes are breaking viz previous OCaml versions (and vanilla Cil), I updated the major version number.