add call to grew_gui_dev when needed

src/grew_main.ml

@@ -29,7 +29,8 @@ let _ =
   | Grew_args.Test -> failwith "No test available"
 
   | Grew_args.Gui args ->
-    match Unix.system ("grew_gui " ^args) with
+    let gui_exec = if Sys.argv.(0) = "grew_dev" then "grew_gui_dev" else "grew_gui" in
+    match Unix.system (gui_exec ^ " " ^ args) with
     | Unix.WEXITED i when i <> 0 ->
       Log.warning "It seems that grew_gui is not installed on your system. Try to run \"opam install grew_gui\""
     | _ -> ()