dune-build-info is not working on flambda1 switch

[zapashcanon]

Hi,

I have a program where I'm getting this error when trying to use dune-build-info on an Flambda1 switch:

$ dune b @install --profile release
File "_none_", line 1:                   
Error (warning 58 [no-cmx-file]): no cmx file was found in path for module Build_info__Build_info_data, and its interface was not compiled with -opaque

It works on closure.

Moreover for some reason, using --profile release does not make the warning non fatal.