[build] Split stdlib to it's own opam package.

We introduce a new package structure for Coq:

- `coq-core`: Coq's OCaml tools code and plugins
- `coq-stdlib`: Coq's stdlib [.vo files]
- `coq`: meta-package that pulls `coq-{core,stdlib}`

This has several advantages, in particular it allows to install Coq
without the stdlib which is useful in several scenarios, it also open
the door towards a versioning of the stdlib at the package level.

The main user-visible change is that Coq's ML development files now
live in `$lib/coq-core`, for compatibility in the regular build we
install a symlink and support both setups for a while.

Note that plugin developers and even `coq_makefile` should actually
rely on `ocamlfind` to locate Coq's OCaml libs as to be more robust.

There is a transient state where we actually look for both
`$coqlib/plugins` and `$coqlib/../coq-core/plugins` as to support
the non-ocamlfind plus custom variables.

This will be much improved once #13617 is merged (which requires this
PR first), then, we will introduce a `coq.boot` library so finally
`coqdep`, `coqchk`, etc... can share the same path setup code.

IMHO the plan should work fine.

1 files changed, 4 insertions, 10 deletions

diff --git a/coq.opam b/coq.opam
index 88e81abf46..3bc3d4db74 100644
--- a/coq.opam
+++ b/coq.opam
@@ -20,15 +20,12 @@ homepage: "https://coq.inria.fr/"
 doc: "https://coq.github.io/doc/"
 bug-reports: "https://github.com/coq/coq/issues"
 depends: [
-  "ocaml" {>= "4.05.0"}
-  "dune" {>= "2.5.0"}
-  "ocamlfind" {>= "1.8.1"}
-  "zarith" {>= "1.10"}
-  "ounit2" {with-test}
+  "dune" {>= "2.5"}
+  "coq-core" {= version}
+  "coq-stdlib" {= version}
 ]
 build: [
-# Disabled until Dune 2.8 is available
-# ["dune" "subst"] {pinned}
+  ["dune" "subst"] {pinned}
   [
     "dune"
     "build"
@@ -42,6 +39,3 @@ build: [
   ]
 ]
 dev-repo: "git+https://github.com/coq/coq.git"
-build-env: [
-  [ COQ_CONFIGURE_PREFIX = "%{prefix}" ]
-]