The fix to allow dune-build-info to work with flambda that was made in #3599 has been undone by #5049 . @hhugo, was this removal of Sys.opaque_identity necessary for jsoo support?

Specifications

• Version of dune (output of dune --version): 3.4.1
• Version of ocaml (output of ocamlc --version): 4.14.0
• Operating system (distribution and version): macos 12.5 and linux centos 7