5.9.2 broken on msvc

[Alizter]

It seems that 5.9.2 has broken on Windows with msvc. See here:

https://github.com/ocaml/dune/actions/runs/17291707204/job/49080921693

To reproduce, compile on Windows together with system-msvc. It seems the Windows coverage in your CI is missing this and only mingw was being tested. Building something like ocaml-compiler.5.3.0,system-msvc should be enough.

[hhugo]

I wonder if this got fixed by #1074. @Alizter, could you check ?

[Alizter]

Looks fixed to me

ocaml/dune#12453