Does not compile with recent OCaml due to use of Pervasives

[burgerdev]

$ dune build
File "src/curve.ml", line 75, characters 32-42:
75 |         aux x1 x2 x3 z2 z3 swap Pervasives.(t - 1)
                                     ^^^^^^^^^^
Error (alert deprecated): module Stdlib.Pervasives
Use Stdlib instead.

If you need to stay compatible with OCaml < 4.07, you can use the 
stdlib-shims library: https://github.com/ocaml/stdlib-shims
File "src/curve.ml", line 84, characters 28-38:
84 |     aux x1 x2 x3 z2 z3 swap Pervasives.(E.bits - 1)
                                 ^^^^^^^^^^
Error (alert deprecated): module Stdlib.Pervasives
Use Stdlib instead.

If you need to stay compatible with OCaml < 4.07, you can use the 
stdlib-shims library: https://github.com/ocaml/stdlib-shims