anchor.diff:  
   assert useX11 -> (gtk2 != null && vte != null && gtkdialog != null);
   assert rubyBindings -> ruby != null;
  -assert pythonBindings -> python != null;
  +assert pythonBindings -> python3 != null;
   
   
   let
  
positive.code:         if ! grep -F "CS_TIP=${cs_tip}" shlr/Makefile; then echo "CS_TIP mismatch"; exit 1; fi
          # When using meson, it expects capstone source relative to build directory
          mkdir -p build/shlr
          ln -s ${capstone} build/shlr/capstone
        '';
  
        postInstall = ''
          ln -s $out/bin/radare2 $out/bin/r2
          install -D -m755 $src/binr/r2pm/r2pm $out/bin/r2pm
        '';
  
        mesonFlags = [
          "-Dr2_version_commit=${version_commit}"
          "-Dr2_gittap=${gittap}"
          "-Dr2_gittip=${gittip}"
          # 2.8.0 expects this, but later it becomes an option with default=false.
          "-Dcapstone_in_builddir=true"
  
          "-Duse_sys_openssl=true"
          "-Duse_sys_zlib=true"
        ];
  
        enableParallelBuilding = true;
  
        nativeBuildInputs = [ pkgconfig ninja meson ];
        buildInputs = [ readline libusb libewf perl zlib openssl libuv ]
          ++ optional useX11 [gtkdialog vte gtk2]
          ++ optional rubyBindings [ruby]
          ++ optional pythonBindings [python]
          ++ optional luaBindings [lua];
  
        meta = {
          description = "unix-like reverse engineering framework and commandline tools";
          homepage = http://radare.org/;
          license = stdenv.lib.licenses.gpl2Plus;
          maintainers = with stdenv.lib.maintainers; [raskin makefu mic92];
          platforms = with stdenv.lib.platforms; linux;
          inherit version;
        };
  
negative.code: {stdenv, fetchFromGitHub
  , buildPackages
  , callPackage
  , pkgconfig
  , libusb, readline, libewf, perl, zlib, openssl
  , libuv, file, libzip, xxHash
  , gtk2 ? null, vte ? null, gtkdialog ? null
  , python3 ? null
  , ruby ? null
  , lua ? null
  , useX11, rubyBindings, pythonBindings, luaBindings
  