[BUG] js_of_ocaml-compiler does not compile with menhir.20200525

[kit-ty-kate]

Using the master branch, the following error appears with a recent enough opam-repository:

-     ocamlopt compiler/lib/.js_of_ocaml_compiler.objs/native/js_of_ocaml_compiler__Js_parser.{cmx,o} (exit 2)
- (cd _build/default && /home/opam/.opam/4.10.0/bin/ocamlopt.opt -w -40 -w -7-37 -safe-string -g -I compiler/lib/.js_of_ocaml_compiler.objs/byte -I compiler/lib/.js_of_ocaml_compiler.objs/native -I /home/opam/.opam/4.10.0/lib/biniou -I /home/opam/.opam/4.10.0/lib/easy-format -I /home/opam/.opam/4.10.0/lib/menhirLib -I /home/opam/.opam/4.10.0/lib/ocaml/compiler-libs -I /home/opam/.opam/4.10.0/lib/yojson -intf-suffix .ml -no-alias-deps -open Js_of_ocaml_compiler -o compiler/lib/.js_of_ocaml_compiler.objs/native/js_of_ocaml_compiler__Js_parser.cmx -c -impl compiler/lib/js_parser.pp.ml)
- File "compiler/lib/js_parser.ml", line 5, characters 2-42:
- 5 |   MenhirLib.StaticVersion.require_20200211
-       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- Error: Unbound value MenhirLib.StaticVersion.require_20200211