anchor.diff:  }:
   
   with pkgs;
  +with stdenv.lib;
   
   stdenv.mkDerivation rec {
   
  
positive.code: 
    prefixKey = "-prefix ";
  
    inherit doCheck;
  
  }
  
negative.code:   ] else []) ++ (if doCheck then
  
      # Test-suite dependencies
      # ncurses is required to build an OCaml REPL
      optional (!versionAtLeast ocaml.version "4.07") ncurses
      ++ [
      python
  