Bug report

export in library works only for last entry module

What is the current behavior?

in webpack config like:

module.exports = {
  entry: ["a", "b", "c"],
  output: {
    library: { type: "global" }
  }
};

only exports from c will be used

If the current behavior is a bug, please provide the steps to reproduce.

https://github.com/TGRHavoc/webpack-mvp

What is the expected behavior?
should use all exports

Other relevant information:
webpack version: latest
Node.js version:
Operating System:
Additional tools: