File "command line", line 1: Error: Unbound module Dune__exe

I have a bucklescript project and there is this message for every file in my project:

```
File "command line", line 1:
Error: Unbound module Dune__exe
```

When I run `bsb -make-world -w`, it will compile just fine.

Start by reproducing the error in the BuckleScript project while using the language server, then compare it with the successful `bsb -make-world -w` build. Trace where the language server invokes compilation and determine why `Dune__exe` is unresolved; done means the per-file error no longer appears.

Written by the indexing model from the issue text.