Update toolchain 3

bin/Ppx.re

@@ -1,10 +1,25 @@
 open Migrate_parsetree;
 
-let mapper = Mapper.getMapper(_ => ());
+let mapper = (_, _) => Mapper.getMapper(_ => ());
 
 let _ =
-  Driver.register(~name="ReactIntl", ~args=[], Versions.ocaml_current, (_, _) =>
-    mapper
-  );
+  Driver.register(~name="ReactIntl", ~args=[], Versions.ocaml_409, mapper);
 
-let _ = Driver.run_as_ppx_rewriter();
+// Source: https://github.com/reasonml-community/graphql_ppx/blob/master/src/bucklescript_bin/Bin.re
+let argv =
+  switch (Sys.argv |> Array.to_list) {
+  | [program, ...rest] =>
+    switch (List.rev(rest)) {
+    | [output_file, input_file, ...args] =>
+      List.concat([
+        [program],
+        List.rev(args),
+        [input_file, "-o", output_file, "--dump-ast", "--embed-errors"],
+      ])
+      |> Array.of_list
+    | _ => Sys.argv
+    }
+  | _ => Sys.argv
+  };
+
+let () = Driver.run_main(~argv, ());