fix(ssr): dont transform process.env. in ssr

[bluwy]

Description

In SSR and the SSR target is node, process.env. will be left as is without transformation. Currently, process.env.FOO will always be transformed as ({}).FOO, which is undesirable when running in node.

Additional context

Supersedes #4192 by @GrygrFlzr (most of the code is borrowed there and we should attribute GrygrFlzr too)
Fixes #3176

Re #3176 (comment), @benmccann and I had agreed that we should continue replacing process.env. in client, but also warn the user that it would be undefined. I can make another PR for this if is desirable.

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[sphinxc0re]

It seems to me like this did not fix the problem. process.env. is still replaced in production builds with adapter-node in sveltekit

[bluwy]

@sphinxc0re This fix isn't released in the latest SvelteKit version yet. We're waiting for a stable Vite release before doing so.

[sphinxc0re]

Oh! Okay, I didn't know that 😅 my bad

[sebazelonka]

It seems to me like this did not fix the problem. process.env. is still replaced in production builds with adapter-node in sveltekit

any workaround to make it work?

[bluwy]

You can temporarily do process.env["SOMETHING"] as mentioned in #3176. Though Vite 2.7.0 should be coming soon now.