title: ReferenceError: regeneratorRuntime is not defined
body: <p>I'm using <code>rollup</code> to build a module from my project, and it's not including <code>regeneratorRuntime</code>. What am I missing here?</p>
  
  <pre><code>module.exports = {
    external: [],
    entry: './src/appProxypass/index.js',
    dest: './packages/proxypass-app/index.js',
    format: 'cjs',
    plugins: [
      require('rollup-plugin-commonjs')({
      }),
      require('rollup-plugin-babel')({
        babelrc: false,
        runtimeHelpers: true,
        // externalHelpers: true,
        'presets': [
          'es2015-rollup',
          'stage-2'
        ],
        'plugins': [
          'transform-async-to-generator',
          'syntax-async-functions',
          'transform-flow-strip-types',
          'transform-class-properties'
        ],
        exclude: 'node_modules/**'
      }),
      require('rollup-plugin-cleanup')()
    ]
  }
  </code></pre>