This PR kind of inline the logic previously encoded by skip-* parameters. We know have to go over all step understand what's done for what version. I think this is going in the wrong direction.
Js_of_ocaml-compiler depend on the latest version of sedlex. (See https://github.com/ocsigen/js_of_ocaml/blob/480cee7c455be33345c1f7f7b1edf80076fe50c1/js_of_ocaml-compiler.opam#L22). You don't seem...