avoid undefined process in webpack v5

[pro-wh]

Webpack 5 no longer provides a polyfill for process. This adds a check so that we don't crash when immediately reaching for process.browser.

[rvagg]

Ahh, good catch, I haven't touched v5 yet so am flying a little blind. Would it be safer to global.process this to avoid invoking any kind of automatic bundle detection like it's doing with Buffer?

[pro-wh]

I've had nothing come up during compilation to the effect that it recommends something for polyfilling process. What I've seen about webpack 5 is that it no longer does this automatic polyfill bundling.

[rvagg]

ok, we'll see then I guess! thanks for this and the other PRs, great work

[pro-wh]

Thanks for going through our changes (: