drive-by contributions, as I was playing around with this (it has better
support for the `num` library, it seems.)
js_of_ocaml: 3.4.0 -> 3.5.2
ocamlPackages.js_of_ocaml-ppx_deriving_json: use ppxlib-0.12.0
ocamlPackages.eliom: 6.8.0 → 6.10.1
ocamlPackages.ocsigen-toolkit: 2.2.0 → 2.5.0
ocamlPackages.ocsigen-start: 2.7.0 → 2.16.1
Co-authored-by: Vincent Laporte <Vincent.Laporte@gmail.com>