modubinascii: Add, with hexlify() implementation.
diff --git a/py/builtin.h b/py/builtin.h
index a673615..a63752c 100644
--- a/py/builtin.h
+++ b/py/builtin.h
@@ -95,3 +95,4 @@
 extern const mp_obj_module_t mp_module_ure;
 extern const mp_obj_module_t mp_module_uheapq;
 extern const mp_obj_module_t mp_module_uhashlib;
+extern const mp_obj_module_t mp_module_ubinascii;