Fix duplicate export error (e.g. when importing Cheerio)

[caleb531]

Fixes rollup/rollup#1637

I've tried to follow @kzc's patch and test cases as closely as I could, but please let me know if I need to make any changes.

Thanks,
Caleb

[lukastaegert]

Looks great, sorry to have kept you waiting 🎉

[caleb531]

@lukastaegert Great, thank you! When could I expect the next release of rollup-plugin-commonjs?

[lukastaegert]

Give me a few more minutes 😀

[lukastaegert]

Oh no, maybe I overestimated my powers here which only seem to extend to merging PRs put not to publishing new versions. I will PM @Rich-Harris as he will probably need to do this.

[lukastaegert]

Until @Rich-Harris is back at the internet to publish a new version, you can install a version containing this fix via

npm install github:rollup-plugin-commonjs@rollup/rollup-plugin-commonjs#bundled-v8.2.3

which should contain all necessary build artefacts.