core/pkgs/build-support/fetchdarcs/default.nix

{ stdenvNoCC, darcs, cacert, lib }:

lib.makeOverridable
({ url, rev ? null, context ? null, sha256 ? "", name ? "fetchdarcs" }:

  stdenvNoCC.mkDerivation {
    builder = ./builder.sh;
    nativeBuildInputs = [ cacert darcs ];

    outputHashAlgo = "sha256";
    outputHashMode = "recursive";
    outputHash = sha256;

    inherit url rev context name;
  })