Revert "Follow c_compiler links for a better ccomp_type detection"

This reverts commit 5df51fd.

src/dune_rules/context.ml

@@ -901,7 +901,7 @@ let best_mode t : Mode.t =
 let cc_g (ctx : t) =
   match ctx.lib_config.ccomp_type with
   | Msvc -> []
-  | _ -> [ "-g" ]
+  | Other _ -> [ "-g" ]
 
 let name t = t.name
 

src/dune_rules/foreign_rules.ml

@@ -94,7 +94,7 @@ let build_c ~kind ~sctx ~dir ~expander ~include_flags (loc, src, dst) =
   let output_param =
     match ctx.lib_config.ccomp_type with
     | Msvc -> [ Command.Args.Concat ("", [ A "/Fo"; Target dst ]) ]
-    | _ -> [ A "-o"; Target dst ]
+    | Other _ -> [ A "-o"; Target dst ]
   in
   Super_context.add_rule sctx ~loc
     ~dir

src/dune_rules/lib_config.ml

@@ -53,4 +53,4 @@ let get_for_enabled_if t ~var =
 let linker_can_create_empty_archives t =
   match t.ccomp_type with
   | Msvc -> false
-  | _ -> true
+  | Other _ -> true

src/dune_rules/lib_rules.ml

@@ -37,7 +37,7 @@ let build_lib (lib : Library.t) ~sctx ~modules ~expander ~flags ~dir ~mode
         (* https://github.com/ocaml/dune/issues/119 *)
         match ctx.lib_config.ccomp_type with
         | Msvc -> msvc_hack_cclibs
-        | _ -> Fun.id
+        | Other _ -> Fun.id
       in
       let obj_deps =
         Build.paths (Cm_files.unsorted_objects_and_cms cm_files ~mode)
@@ -145,7 +145,7 @@ let ocamlmklib ~loc ~c_library_flags ~sctx ~dir ~expander ~o_files ~archive_name
                   | Msvc ->
                     let cclibs = msvc_hack_cclibs cclibs in
                     Command.quote_args "-ldopt" cclibs
-                  | _ -> As cclibs))
+                  | Other _ -> As cclibs))
          ; Hidden_targets targets
          ])
   in

src/ocaml-config/dune

@@ -1,5 +1,5 @@
 (library
  (name ocaml_config)
  (public_name dune-private-libs.ocaml-config)
- (libraries stdune dune_re dune_lang)
+ (libraries stdune dune_lang)
  (synopsis "[Internal] Interpret the output of 'ocamlc -config'"))

src/ocaml-config/ocaml_config.ml

@@ -55,57 +55,20 @@ end
 module Ccomp_type = struct
   type t =
     | Msvc
-    | Gcc
-    | Clang
     | Other of string
 
   let to_dyn =
     let open Dyn.Encoder in
     function
     | Msvc -> constr "Msvc" []
-    | Gcc -> constr "Gcc" []
-    | Clang -> constr "Clang" []
     | Other s -> constr "Other" [ string s ]
 
-  let readlinks bin =
-    let path = Env.(path initial) in
-    let rec aux i start =
-      (* Enfore same depth limit as (old) linux [path_resolution] *)
-      if i >= 8 then
-        start
-      else
-        let path =
-          Bin.which ~path start
-          |> Option.map ~f:Path.to_absolute_filename
-          |> Option.value ~default:bin
-        in
-        try
-          let end_ = Unix.readlink path in
-          if end_ = start then
-            start
-          else
-            aux (i + 1) end_
-        with Unix.Unix_error _ -> start
-    in
-    aux 0 bin
-
-  let of_string ~c_compiler ccomp_type =
-    let re name =
-      Dune_re.(seq [ rep any; char '-'; str name; rep any ]) |> Dune_re.compile
-    in
-    let c_compiler = readlinks c_compiler in
-    match (ccomp_type, c_compiler) with
-    | "msvc", _ -> Msvc
-    | _, "gcc" -> Gcc
-    | _, "clang" -> Clang
-    | _, s when Dune_re.execp (re "gcc") s -> Gcc
-    | _, s when Dune_re.execp (re "clang") s -> Clang
-    | s, _ -> Other s
+  let of_string = function
+    | "msvc" -> Msvc
+    | s -> Other s
 
   let to_string = function
     | Msvc -> "msvc"
-    | Gcc -> "gcc"
-    | Clang -> "clang"
     | Other s -> s
 end
 
@@ -493,7 +456,7 @@ let make vars =
         (get_opt vars "standard_runtime")
         ~default:"the_standard_runtime_variable_was_deleted"
     in
-    let ccomp_type = Ccomp_type.of_string ~c_compiler (get vars "ccomp_type") in
+    let ccomp_type = Ccomp_type.of_string (get vars "ccomp_type") in
     let bytecomp_c_libraries = get_words vars "bytecomp_c_libraries" in
     let native_c_libraries = get_words vars "native_c_libraries" in
     let cc_profile = get_words vars "cc_profile" in

src/ocaml-config/ocaml_config.mli

@@ -52,8 +52,6 @@ end
 module Ccomp_type : sig
   type t =
     | Msvc
-    | Gcc
-    | Clang
     | Other of string
 
   val to_dyn : t -> Stdune.Dyn.t