Merge pull request #2282 from theacodes/native-if-available

Make the @micropython.native decorator no-op if support isn't enabled

py/compile.c

@@ -775,13 +775,22 @@ STATIC bool compile_built_in_decorator(compiler_t *comp, int name_len, mp_parse_
     qstr attr = MP_PARSE_NODE_LEAF_ARG(name_nodes[1]);
     if (attr == MP_QSTR_bytecode) {
         *emit_options = MP_EMIT_OPT_BYTECODE;
-#if MICROPY_EMIT_NATIVE
+    // @micropython.native decorator.
     } else if (attr == MP_QSTR_native) {
+        // Different from MicroPython: native doesn't raise SyntaxError if native support isn't
+        // compiled, it just passes through the function unmodified.
+        #if MICROPY_EMIT_NATIVE
         *emit_options = MP_EMIT_OPT_NATIVE_PYTHON;
+        #else
+        return true;
+        #endif
+    #if MICROPY_EMIT_NATIVE
+    // @micropython.viper decorator.
     } else if (attr == MP_QSTR_viper) {
         *emit_options = MP_EMIT_OPT_VIPER;
-#endif
+    #endif
     #if MICROPY_EMIT_INLINE_ASM
+    // @micropython.asm_thumb decorator.
     } else if (attr == ASM_DECORATOR_QSTR) {
         *emit_options = MP_EMIT_OPT_ASM;
     #endif