Restored common_option definition. Was removed by a non delicate merge.

src/options.ml

@@ -119,11 +119,10 @@ let set_mpfr prec =
 let set_backend s =
   output := s;
   Backends.setup s
-  
-let options =
-[ "-d", Arg.Set_string dest_dir,
-"uses the specified directory \x1b[4mdir\x1b[0m as root for generated/imported object and C files <default: .>";
-"-I", Arg.Set_string include_dir, "Include directory";
+
+let common_options =
+  [ "-d", Arg.Set_string dest_dir, "uses the specified \x1b[4mdirectory\x1b[0m as root for generated/imported object and C files <default: .>";
+    "-I", Arg.String add_include_dir, "sets include \x1b[4mdirectory\x1b[0m";
     "-node", Arg.Set_string main_node, "specifies the \x1b[4mmain\x1b[0m node";
     "-print-types", Arg.Set print_types, "prints node types";
     "-print-clocks", Arg.Set print_clocks, "prints node clocks";