Implement kwargs for builtin open() and _io.FileIO
This makes open() and _io.FileIO() more CPython compliant.
The mode kwarg is fully iplemented.
The encoding kwarg is allowed but not implemented; mainly to allow
the tests to specify encoding for CPython, see #874
diff --git a/py/builtin.h b/py/builtin.h
index 01ec22d..a69712b 100644
--- a/py/builtin.h
+++ b/py/builtin.h
@@ -25,7 +25,7 @@
*/
mp_obj_t mp_builtin___import__(mp_uint_t n_args, mp_obj_t *args);
-mp_obj_t mp_builtin_open(mp_uint_t n_args, const mp_obj_t *args);
+mp_obj_t mp_builtin_open(mp_uint_t n_args, const mp_obj_t *args, mp_map_t *kwargs);
MP_DECLARE_CONST_FUN_OBJ(mp_builtin___build_class___obj);
MP_DECLARE_CONST_FUN_OBJ(mp_builtin___import___obj);