py: Make mp_binary_set_val work on big endian machine.
diff --git a/py/modstruct.c b/py/modstruct.c
index 8122a96..8c0cafd 100644
--- a/py/modstruct.c
+++ b/py/modstruct.c
@@ -160,7 +160,7 @@
 }
 MP_DEFINE_CONST_FUN_OBJ_2(struct_unpack_obj, struct_unpack);
 
-STATIC mp_obj_t struct_pack(uint n_args, mp_obj_t *args) {
+STATIC mp_obj_t struct_pack(mp_uint_t n_args, const mp_obj_t *args) {
     // TODO: "The arguments must match the values required by the format exactly."
     const char *fmt = mp_obj_str_get_str(args[0]);
     char fmt_type = get_fmt_type(&fmt);
@@ -169,7 +169,7 @@
     mp_obj_t res = mp_obj_str_builder_start(&mp_type_bytes, size, &p);
     memset(p, 0, size);
 
-    for (uint i = 1; i < n_args; i++) {
+    for (mp_uint_t i = 1; i < n_args; i++) {
         mp_uint_t sz = 1;
         if (unichar_isdigit(*fmt)) {
             sz = get_fmt_num(&fmt);