test(melange): accept ppx loc-filename in fixtures

test/blackbox-tests/test-cases/melange/preprocess.t

@@ -39,13 +39,17 @@ Reason dialect preprocessor to the PPX driver.
 
   $ cat > ppx/reason_ppx.ml <<'EOF'
   > let () =
-  >   Array.iter
-  >     (fun arg ->
+  >   let rec loop = function
+  >     | [] -> ()
+  >     | "-loc-filename" :: _ :: rest -> loop rest
+  >     | arg :: rest ->
   >       if Filename.check_suffix arg ".re" || Filename.check_suffix arg ".rei"
   >       then (
   >         Printf.eprintf "ppx saw Reason source: %s\n" arg;
-  >         exit 1))
-  >     Sys.argv
+  >         exit 1)
+  >       else loop rest
+  >   in
+  >   loop (Array.to_list Sys.argv)
   > ;;
   > let () = Ppxlib.Driver.register_transformation "reason_ppx"
   > EOF

test/blackbox-tests/test-cases/per-module-lib-deps/melange-pps-runtime-libs.t

@@ -41,6 +41,7 @@ stub-driver pattern in `ppx-runtime-libraries.t`).
   >     ; ("--impl", Arg.Set_string (ref ""), "")
   >     ; ("--as-ppx", Arg.Set (ref false), "")
   >     ; ("--cookie", Arg.Set (ref false), "")
+  >     ; ("-loc-filename", Arg.String ignore, "")
   >     ]
   >   in
   >   let anon _ = () in
@@ -52,7 +53,10 @@ The melange.emit preprocesses with `hello_ppx`:
 
   $ mkdir me
   $ cat > me/dune <<EOF
-  > (melange.emit (target output) (preprocess (pps hello_ppx)))
+  > (melange.emit
+  >  (target output)
+  >  (emit_stdlib false)
+  >  (preprocess (pps hello_ppx)))
   > EOF
   $ cat > me/foo.ml <<EOF
   > let _ = ()