spurious warning on "use_menhir" tag #6502
Original bug ID: 6502
Having "true: use_menhir" in _tags, I get the following warning:
Warning: the tag "use_menhir" is not used in any flag declaration, so it will have no effect; it may be a typo. Otherwise use
I believe this warning is spurious, since "use_menhir" does take effect.
Suggested fix, to be confirmed by ocamlbuild experts: in ocamlbuild/main.ml, add "use_menhir" to the list "builtin_useful_tags" on line 61.