Expose __import__() function.

py/builtin.h

 mp_obj_t mp_builtin___import__(int n_args, mp_obj_t *args);
 
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin___build_class___obj);
+MP_DECLARE_CONST_FUN_OBJ(mp_builtin___import___obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin___repl_print___obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin_abs_obj);
 MP_DECLARE_CONST_FUN_OBJ(mp_builtin_all_obj);

py/builtinimport.c

@@ -95,3 +95,4 @@ mp_obj_t mp_builtin___import__(int n_args, mp_obj_t *args) {
 
     return module_obj;
 }
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin___import___obj, 1, 5, mp_builtin___import__);

py/qstrdefs.h

@@ -4,6 +4,7 @@
 Q(__build_class__)
 Q(__class__)
 Q(__doc__)
+Q(__import__)
 Q(__init__)
 Q(__locals__)
 Q(__main__)

py/runtime.c

@@ -110,6 +110,7 @@ void rt_init(void) {
 
     // built-in core functions
     mp_map_add_qstr(&map_builtins, MP_QSTR___build_class__, (mp_obj_t)&mp_builtin___build_class___obj);
+    mp_map_add_qstr(&map_builtins, MP_QSTR___import__, (mp_obj_t)&mp_builtin___import___obj);
     mp_map_add_qstr(&map_builtins, MP_QSTR___repl_print__, (mp_obj_t)&mp_builtin___repl_print___obj);
 
     // built-in types