squashfs: add zstd support

[razum2um]

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Please merge this PR first Homebrew/formula-patches#277
After that I'll update patch url to proper one

See working tap here: https://github.com/lunatic-cat/homebrew-tap

[javian]

It seems that the maintainer is working on this git repo https://github.com/plougher/squashfs-tools/ which includes zstd support . Could you check if there's a release available or if one is planned ?

[razum2um]

Frankly speaking, I just missed that repo, sorry

I see 3.* tags there, but that's not releases.
Link to the issue about next release: plougher/squashfs-tools#54

Also link to previous attempt to update this in brew #32818

[fxcoudert]

We do not want to add patches for extra functionality, we only use patches for critical issues (build failure, security, major crash). We try to ship software as closely as released by upstream, as we cannot (and do not want to) become de facto maintainers for 4000+ software.

The existing tap is probably the best solution for now.