config.nix

    fish = lib.overrideDerivation fish (attrs: rec {
      name = "fish-${version}-dev";
      version = "2.3.1";
      src = fetchFromGitHub {
        owner = "fish-shell";
        repo = "fish-shell";
        rev = "89e48ba0b3b2ff0f254443117483814402f8f6cd";
        sha256 = "1hznlfa75l24bwdx5rkwnr5ni4x2zssh2n1m3jv10mnsi0slwrgw";
      };
      buildInputs = fish.buildInputs ++ [ autoconf ];
      buildPhase = ''
        autoconf
      '';
    });