[Libguestfs] [PATCH 0/9] build: Require OCaml >= 4.02.

Per my previous email: https://www.redhat.com/archives/libguestfs/2017-September/msg00203.html I'd like to talk about requiring a more modern version of the OCaml compiler. These commits show some of the code changes which would be possible with OCaml >= 3.12 [which it turns out we already require by accident] and also with OCaml >= 4.02. The latter is my favoured option. Rich.