Local opam file: URLs and dependency on `cppo_ocamlbuild`

[smondet]

The URLs point to https://github.com/whitequark.

And the dependency on cppo_ocamlbuild seems missing (it's a new package now separate from cppo).

[whitequark]

The URLs point to https://github.com/whitequark.

This isn't an immediate problem FWIW as GitHub has a redirect.

And the dependency on cppo_ocamlbuild seems missing (it's a new package now separate from cppo).

That's because that was just merged a few hours ago.

[catalin-hritcu]

cppo_ocamlbuild dependency still missing on opam

[gasche]

I just re-checked, and the cppo_ocamlbuild dependency is present in both the opam-repository packages, and in the upstream opam file. I thus believe that the cppo_ocamlbuild issue should now be fixed.