BUILD: try to fix jenkins + 3.12
BUILD: try to fix jenkins + 3.12

alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml