libctypes-ocaml-dev - 0.20.1-1 main

The ocaml-ctypes library makes it possible to call C functions
directly from OCaml without writing or generating C code. The core
of the library is a set of combinators for describing C types --
scalars, functions, structs, unions, arrays, and pointers to values
and functions. Type descriptions can then be used to bind native
functions and values.
.
This package contains all the development stuff you need to use
ocaml-ctypes.