anchor.diff:  
       installPhase = ''
          mkdir -p $out/bin
  -       cp -R {include,lib_pypy,lib-python,pypy-c} $out/
  -       ln -s $out/pypy-c $out/bin/pypy
  +       mkdir -p $out/pypy-c
  +       cp -R {include,lib_pypy,lib-python,pypy-c} $out/pypy-c
  +       ln -s $out/pypy-c/pypy-c $out/bin/pypy
          chmod +x $out/bin/pypy
          # TODO: compile python files?
       '';
  
positive.code:         --replace "ncurses/curses.h" "${ncurses}/include/curses.h" \
          --replace "ncurses/term.h" "${ncurses}/include/term.h" \
          --replace "libraries = ['curses']" "libraries = ['ncurses']"
  
        #substituteInPlace rpython/translator/platform/__init__.py \
        #  --replace "return include_dirs" "return tuple(\"{expat}\", *include_dirs)" \
        #  --replace "return library_dirs" "return tuple(\"{expat}\", *library_dirs)"
      '';
  
      TERMINFO = "${ncurses}/share/terminfo/";
  
negative.code:       sha256 = "0g2cajs6m3yf0lak5f18ccs6j77cf5xvbm4h6y5l1qlqdc6wk48r";
      };
  
      buildInputs = [ bzip2 openssl pkgconfig pythonFull libffi ncurses expat sqlite ]
        ++ stdenv.lib.optional (stdenv ? gcc && stdenv.gcc.libc != null) stdenv.gcc.libc
        ++ stdenv.lib.optional zlibSupport zlib;
  
      C_INCLUDE_PATH = stdenv.lib.concatStringsSep ":" (map (p: "${p}/include") buildInputs);
      LIBRARY_PATH = stdenv.lib.concatStringsSep ":" (map (p: "${p}/lib") buildInputs);
      LD_LIBRARY_PATH = LIBRARY_PATH;
  
      preConfigure = ''
        substituteInPlace Makefile \
  