anchor.diff: -{stdenv, fetchFromGitHub, fetchgit, fetchurl, fetchpatch, pkgconfig, libusb, readline, libewf, perl, zlib, openssl, git,
  -gtk2 ? null, vte ? null, gtkdialog ? null,
  -python ? null,
  -ruby ? null,
  -lua ? null,
  -useX11, rubyBindings, pythonBindings, luaBindings}:
  +{stdenv, fetchFromGitHub, pkgconfig, libusb, readline, libewf, perl, zlib, openssl
  +, gtk2 ? null, vte ? null, gtkdialog ? null
  +, python ? null
  +, ruby ? null
  +, lua ? null
  +, useX11, rubyBindings, pythonBindings, luaBindings
  +}:
   
   assert useX11 -> (gtk2 != null && vte != null && gtkdialog != null);
   assert rubyBindings -> ruby != null;
  
positive.code: 
    enableParallelBuilding = true;
  
    nativeBuildInputs = [ pkgconfig git ];
    buildInputs = [ readline libusb libewf perl zlib openssl]
      ++ optional useX11 [gtkdialog vte gtk2]
      ++ optional rubyBindings [ruby]
  
negative.code:     sha256 = "07x94chkhpn3wgw4pypn35psxq370j6xwmhf1mh5z27cqkq7c2yd";
    };
  
    # do not try to update capstone
    WITHOUT_PULL=1;
  
    postPatch = let
      cs_tip = "4a1b580d069c82d60070d0869a87000db7cdabe2"; # version from $sourceRoot/shlr/Makefile
      capstone = fetchFromGitHub {
        owner = "aquynh";
        repo = "capstone";
        rev = cs_tip;
        sha256 = "0v6rxfpxjq0hf40qn1n5m5wsv1dv6p1j8vm94a708lhvcbk9nkv8";
      };
    in ''
      if ! grep -F "CS_TIP=${cs_tip}" shlr/Makefile; then echo "CS_TIP mismatch"; exit 1; fi
  