knot-resolver: fix LUA_{PATH,CPATH}

[eadwu]

LUA_PATH and LUA_CPATH were both blank beforehand.

Motivation for this change

Enabling DNSSEC, trust_anchors.add_file('/var/cache/kresd/root.keys').

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

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[vcunat]

Hmm, I suppose some lua infra changes have broken this. I'll have a closer look later.

BTW, you don't need to add custom root trust anchor file or explicitly enable DNSSEC validation – you get all that by default without these extra lua packages (via dns-root-data package, as the root TA rotates extremely slowly anyway).

[vcunat]

This was broken by #63108. Unfortunately this PR isn't a full fix, because it doesn't address dependency propagation, in particular some lua dependencies of http are missing.

[teto]

let's fix the original issue. A quickfix might be to use a lua.withPackages as a buildInput ?

[vcunat]

Thanks a lot for reporting this! I pushed a quick-fix in the meantime, and I agree we need to resolve the underlying issue anyway.