fix for ocaml-integers 0.3.0

[ygrek]

ocaml-integers 0.3.0 changed the name of C stubs library, ctypes manually links it in, so the corresponding change in needed. The following patch works, idk if it is too hacky or if it should be a configure check?

diff --git a/Makefile b/Makefile
index fe15a45..d239a28 100644
--- a/Makefile
+++ b/Makefile
@@ -67,7 +67,7 @@ ctypes.public = lDouble complexL ctypes posixTypes ctypes_types
 ctypes.dir = src/ctypes
 ctypes.extra_mls = ctypes_primitives.ml
 ctypes.deps = bigarray bytes integers
-ctypes.linkdeps = integers
+ctypes.linkdeps = integers_stubs
 ctypes.install = yes
 ctypes.install_native_objects = yes
 ifeq ($(XEN),enable)

ref yallop/ocaml-integers#26

[yallop]

This looks sensible to me (but I haven't tested it yet). Could you turn it into a PR?

I don't think we should add a configure-time check, but we can change the opam constraint to be "integers" { < "0.3.0" }.

[yallop]

Also, I expect this will eventually be made obsolete by @avsm's work in #588.

[ygrek]

you meant "integers" >= "0.3.0" I guess