FFI sample code build issue

[gruntguo]

I am a beginer of ocaml, when I build the example, follow the sample(ffi chapters), get following error.
then I made a change in dune , it works; not sure if it is my env issue or something else.
Thanks for the book

file:
+++
book/book/foreign-function-interface/examples/ffi/ncurses/dune

error:
+++
3 | (libraries ctypes-foreign.threaded)
^^^^^^^^^^^^^^^^^^^^^^^
Error: Library "ctypes-foreign.threaded" not found.

diff 
+++
$ diff dune.orig  dune
3c3
<   (libraries ctypes-foreign.threaded)
---
>   (libraries ctypes.foreign)

[yminsky]

The book was out of date with how ctypes is now packaged and how it's invoked via Dune. Take another look!