[coqtop] Give priority to stdlib load path over current directory

When initilazing the load path, coqtop adds implicit bindings for stdlib
and for the current directory (-R stdlib Coq -R . ""). In case of
a clash, the binding of the current directory had priority, which makes
it impossible to edit stdlib files (when they Require files from the
same directory) using PG, or from CoqIDE when launched from the directory
containing the file.

Example to reproduce the problem:

```
cd plugins/omega
coqide Omega.v
```

some of the Requires will fail.

1 files changed, 9 insertions, 9 deletions

diff --git a/toplevel/coqinit.ml b/toplevel/coqinit.ml
index e61f830f3..e1d35e537 100644
--- a/toplevel/coqinit.ml
+++ b/toplevel/coqinit.ml
@@ -92,6 +92,14 @@ let libs_init_load_path ~load_init =
   let coqpath = Envars.coqpath in
   let coq_path = Names.DirPath.make [Libnames.coq_root] in
 
+  (* current directory (not recursively!) *)
+  [ { recursive = false;
+      path_spec = VoPath { unix_path = ".";
+                           coq_path = Libnames.default_root_prefix;
+                           implicit = false;
+                           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 ] @
@@ -102,15 +110,7 @@ let libs_init_load_path ~load_init =
   ) @
 
   (* then directories in XDG_DATA_DIRS and XDG_DATA_HOME and COQPATH *)
-  List.map (fun s -> build_userlib_path ~unix_path:s) (xdg_dirs @ coqpath) @
-
-  (* then current directory (not recursively!) *)
-  [ { recursive = false;
-      path_spec = VoPath { unix_path = ".";
-                           coq_path = Libnames.default_root_prefix;
-                           implicit = false;
-                           has_ml = AddTopML }
-    } ]
+  List.map (fun s -> build_userlib_path ~unix_path:s) (xdg_dirs @ coqpath)
 
 (* Initialises the Ocaml toplevel before launching it, so that it can
    find the "include" file in the *source* directory *)