[build] Consolidate stdlib's .v files under a single directory.

Currently, `.v` under the `Coq.` prefix are found in both `theories`
and `plugins`. Usually these two directories are merged by special
loadpath code that allows double-binding of the prefix.

This adds some complexity to the build and loadpath system; and in
particular, it prevents from handling the `Coq.*` prefix in the
simple, `-R theories Coq` standard way.

We thus move all `.v` files to theories, leaving `plugins` as an
OCaml-only directory, and modify accordingly the loadpath / build
infrastructure.

Note that in general `plugins/foo/Foo.v` was not self-contained, in
the sense that it depended on files in `theories` and files in
`theories` depended on it; moreover, Coq saw all these files as
belonging to the same namespace so it didn't really care where they
lived.

This could also imply a performance gain as we now effectively
traverse less directories when locating a library.

See also discussion in #10003

1 files changed, 9 insertions, 3 deletions

diff --git a/toplevel/coqinit.ml b/toplevel/coqinit.ml
index ac348b9646..b353f8aff1 100644
--- a/toplevel/coqinit.ml
+++ b/toplevel/coqinit.ml
@@ -59,6 +59,12 @@ let build_stdlib_path ~load_init ~unix_path ~coq_path ~with_ml =
     path_spec = VoPath { unix_path; coq_path ; has_ml = add_ml; implicit = load_init }
   }
 
+let build_stdlib_ml_path ~dir =
+  let open Loadpath in
+  { recursive = true
+  ; path_spec = MlPath dir
+  }
+
 let build_userlib_path ~unix_path =
   let open Loadpath in
   { recursive = true;
@@ -100,9 +106,9 @@ let libs_init_load_path ~load_init =
                            has_ml = AddTopML }
     } ] @
 
-  (* then standard library and plugins *)
-  [build_stdlib_path ~load_init ~unix_path:(coqlib/"theories") ~coq_path ~with_ml:false;
-   build_stdlib_path ~load_init ~unix_path:(coqlib/"plugins")  ~coq_path ~with_ml:true ] @
+  (* then standard library *)
+  [build_stdlib_ml_path ~dir:(coqlib/"plugins")] @
+  [build_stdlib_path ~load_init ~unix_path:(coqlib/"theories") ~coq_path ~with_ml:false] @
 
   (* then user-contrib *)
   (if Sys.file_exists user_contrib then