anchor.diff:      ++ (op yamlSupport libyaml);
   
     enableParallelBuilding = true;
  -    
  +
     configureFlags = ["--enable-shared" "--enable-pthread"];
   
     installFlags = stdenv.lib.optionalString docSupport "install-doc";
  
positive.code:   passthru = rec {
      majorVersion = "1.9";
      minorVersion = "3";
      patchLevel = "194";
      libPath = "lib/ruby/${majorVersion}";
      gemPath = "lib/ruby/gems/${majorVersion}";
    };
  
negative.code: 
  stdenv.mkDerivation rec {
    version = with passthru; "${majorVersion}.${minorVersion}-p${patchLevel}";
  
    name = "ruby-${version}";
  
    src = fetchurl {
      url = "ftp://ftp.ruby-lang.org/pub/ruby/1.9/${name}.tar.bz2";
      sha256 = "14c3lp9w7hq3jcmbakw2ngrzd7c81fgqm6skpxwni5k2vzgk8wss";
    };
  
    # Have `configure' avoid `/usr/bin/nroff' in non-chroot builds.
  