自定义引擎 gulp build 报错

clone 了 cocos-creator/engine v1.8-release 分支
执行
npm install
提示:
npm WARN package.json cocos-creator-js@1.7.0 No repository field.
然后执行
gulp build 出现如下错入:
上传中…

    for (let i = 0; i < PLATFORM_MACROS.length; i++) {
         ^^^

SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:373:25)
    at Object.Module._extensions..js (module.js:416:10)
    at Module.load (module.js:343:32)
    at Function.Module._load (module.js:300:12)
    at Module.require (module.js:353:17)
    at require (internal/module.js:12:17)
    at Object.<anonymous> (/Users/xxx/engine/gulp/tasks/engine.js:28:15)
    at Module._compile (module.js:409:26)
    at Object.Module._extensions..js (module.js:416:10)

你的 node.js 版本太低了,升级到 8.x 吧