py: Add "delattr" builtin, conditional on MICROPY_CPYTHON_COMPAT.

py/builtin.h

@@ -42,6 +42,7 @@ MP_DECLARE_CONST_FUN_OBJ_1(mp_builtin_bin_obj);
 MP_DECLARE_CONST_FUN_OBJ_1(mp_builtin_callable_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_compile_obj);
 MP_DECLARE_CONST_FUN_OBJ_1(mp_builtin_chr_obj);
+MP_DECLARE_CONST_FUN_OBJ_2(mp_builtin_delattr_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_dir_obj);
 MP_DECLARE_CONST_FUN_OBJ_2(mp_builtin_divmod_obj);
 MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin_eval_obj);

py/modbuiltins.c

@@ -542,6 +542,13 @@ STATIC mp_obj_t mp_builtin_setattr(mp_obj_t base, mp_obj_t attr, mp_obj_t value)
 }
 MP_DEFINE_CONST_FUN_OBJ_3(mp_builtin_setattr_obj, mp_builtin_setattr);
 
+#if MICROPY_CPYTHON_COMPAT
+STATIC mp_obj_t mp_builtin_delattr(mp_obj_t base, mp_obj_t attr) {
+    return mp_builtin_setattr(base, attr, MP_OBJ_NULL);
+}
+MP_DEFINE_CONST_FUN_OBJ_2(mp_builtin_delattr_obj, mp_builtin_delattr);
+#endif
+
 STATIC mp_obj_t mp_builtin_hasattr(mp_obj_t object_in, mp_obj_t attr_in) {
     qstr attr = mp_obj_str_get_qstr(attr_in);
 
@@ -645,6 +652,9 @@ STATIC const mp_rom_map_elem_t mp_module_builtins_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_compile), MP_ROM_PTR(&mp_builtin_compile_obj) },
     #endif
     { MP_ROM_QSTR(MP_QSTR_chr), MP_ROM_PTR(&mp_builtin_chr_obj) },
+    #if MICROPY_CPYTHON_COMPAT
+    { MP_ROM_QSTR(MP_QSTR_delattr), MP_ROM_PTR(&mp_builtin_delattr_obj) },
+    #endif
     { MP_ROM_QSTR(MP_QSTR_dir), MP_ROM_PTR(&mp_builtin_dir_obj) },
     { MP_ROM_QSTR(MP_QSTR_divmod), MP_ROM_PTR(&mp_builtin_divmod_obj) },
     #if MICROPY_PY_BUILTINS_EVAL_EXEC