haskellPackages.arch-web: unbreak

[berberman]

Motivation for this change

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• 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 nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Added a release notes entry if the change is major or breaking
• Fits CONTRIBUTING.md.

[cdepillabout]

LGTM, thanks for fixing this!

Also, it feels somewhat funny to have this package working in nixpkgs: Arch Linux official and AUR web interface binding. Although I imagine it could be helpful for someone using Nix on Arch.

[berberman]

LOL, I'm a contributor of Haskell package set in Arch Linux official repo, but I do almost all my works on NixOS now XD