109.32.00

- Fixed the slow and memory-consuming compilation of > 100MB `.c` files generated by `ocaml_embed_compiler`.

  This was done by having them contain one big string instead of one big
  array.

- Added more unused-value warnings in plugins.

  If { `Ui` , `M` } are the modules that constitute a given plugin of
  expected module type `S`, then previously we generated a file like:

  ```ocaml
  module Ui : sig
    ...
  end = struct
    ...
  end

  module M : sig
    ...
  end = struct
    ...
  end

  let () = ##register (M : S)
  ```

  Doing that, we did not get unused variables:

  1. for the toplevel of `Ui` if `Ui` does not have a `mli`.
  2. for unused values of `Ui` and `M` if they have an `mli` exporting them.

  OCaml plugin now allows one to get these warnings.  Since (2) is
  rather annoying for utils kind of file, this comes only if a config
  flag is enabled.