Files ocamlbuildlib.cmxa and unix.cmxa make inconsistent assumptions over implementation Unix

[Hector Garcia de Marina]

Hi, I do not know whether this bug should be here. From the project https://github.com/paparazzi/paparazzi , users with Ubuntu 17.10 are experiencing the following problem

+ ocamlfind ocamlopt unix.cmxa -I /usr/lib/ocaml/ocamlbuild /usr/lib/ocaml/ocamlbuild/ocamlbuildlib.cmxa -linkpkg myocamlbuild.ml /usr/lib/ocaml/ocamlbuild/ocamlbuild.cmx -o myocamlbuild
File "myocamlbuild.ml", line 1:
Error: Files /usr/lib/ocaml/ocamlbuild/ocamlbuildlib.cmxa
       and /usr/lib/ocaml/unix.cmxa
       make inconsistent assumptions over implementation Unix
Command exited with code 2.

The maintainers of Paparazzi believe that this is an issue of the Ubuntu distribution. In fact, it seems that other distributions are facing a similar problem https://bugzilla.redhat.com/show_bug.cgi?id=1481916

[Hector Garcia de Marina (noether)]

It seems that the package that contains ocamlbuild has not being updated accordingly?

https://github.com/ocaml/ocamlbuild/issues/264

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Dominique Unruh (unruh-mmci)]

This is independent of paparazzi.

Just typing 'ocamlbuild' in the shell produces the error.

[Dominique Unruh (unruh-mmci)]

The following workaround works for me:

sudo apt remove ocamlbuild
sudo opam install ocamlbuild

This avoids using the broken ocamlbuild from the repository but installs a separate one.

[Kakadu (kakadout)]

I tested ocamlbuild on Ubuntu 22.04 and it looks like this bug is gone.