Add MODULE_INIT_COMPRESSED_FILE definition

[sinkingpoint]

Opening this alongside #3782 to backport the const into libc-0.2 so that we can use it in nix

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[tgross35]

We are slightly changing the workflow here - PRs should target main, then they will get cherry-picked to stable if applicable. So I am going to close this and stable-nominate #3782 (which I will review once I get the chance).