discover: use ARGN instead of custom call to pkgconfig

Author: raphael-proust

config/discover.ml

@@ -397,28 +397,20 @@ let dynamic over libs =
   let (_over,libs) = List.partition (fun l -> List.mem l over) libs in
   (if over <> [] then ["-Wl,--push-state"; "-Wl,-Bdynamic"] @ over @ ["-Wl,--pop-state"] else []) @ libs
 
-(* basically Pkg_config.query_expr_err with --static and no smartness finding pkg-config itself (it is up to the host owner to set it up properly) *)
-let pkg_config ~package ?(expr=package) c =
-  let open C in
-  let run args =
-    Flags.extract_blank_separated_words @@ String.trim @@ Process.run_capture_exn c "pkg-config" @@ [ "--print-errors"] @ args @ [ package ]
-  in
-  match Process.run c "pkg-config" [ "--print-errors"; expr ] with
-  | { exit_code = 0; _ } -> Ok { Pkg_config.libs = run ["--static"; "--libs"]; cflags = run ["--static"; "--cflags"] }
-  | { stderr; _ } -> Error stderr
-
 let main c =
   let cflags, libs =
     match C.ocaml_config_var c "ccomp_type" with
     | Some "cc" ->
        let {C.Pkg_config.cflags; libs} =
          match C.Pkg_config.get c with
          | None -> { cflags = []; C.Pkg_config.libs = [ "-lcurl" ]}
-         | Some _pc ->
-            (match pkg_config c ~package:"libcurl" ~expr:"libcurl >= 7.28.0" with
-            (* static sasl is unusable (requires a lot of dependencies), p11-kit doesn't provide static lib *)
-            (* TODO figure the absence of static lib automatically *)
-            | Ok c -> { c with libs = dynamic ["-lsasl2";"-lp11-kit"] c.libs }
+         | Some pc ->
+            Unix.putenv "PKG_CONFIG_ARGN" "--static";
+            (match C.Pkg_config.query_expr_err pc ~package:"libcurl" ~expr:"libcurl >= 7.28.0" with
+            | Ok c ->
+                (* static sasl is unusable (requires a lot of dependencies), p11-kit doesn't provide static lib *)
+                (* TODO figure the absence of static lib automatically *)
+                { c with libs = dynamic ["-lsasl2";"-lp11-kit"] c.libs }
             | Error err -> C.die "%s" err)
        in
        "-Wall" :: "-Wno-deprecated-declarations" :: cflags, libs