[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, 3 insertions, 2 deletions

diff --git a/Makefile.install b/Makefile.install
index 4977bb38e1..0dd4c1bc24 100644
--- a/Makefile.install
+++ b/Makefile.install
@@ -162,8 +162,9 @@ install-latex:
 	$(INSTALLLIB) tools/coqdoc/coqdoc.sty $(FULLCOQDOCDIR)
 #	-$(UPDATETEX)
 
-install-meta: META.coq
-	$(INSTALLLIB) META.coq $(FULLCOQLIB)/META
+install-meta: META.coq-core
+	$(INSTALLLIB) META.coq-core $(FULLCOQLIB)/META
+	cd $(FULLCOQLIB)/.. && rm -f coq-core && ln -s coq coq-core
 
 # For emacs:
 # Local Variables: