anchor.diff:  
     postFixup = ''
       moveToOutput bin/pcre-config "$dev"
  -  ''
  -    + optionalString (variant != null) ''
  +  '' + optionalString (variant != null) ''
       ln -sf -t "$out/lib/" '${pcre.out}'/lib/libpcre{,posix}.{so.*.*.*,*dylib}
     '';
   
  
positive.code:     '';
  
      platforms = platforms.all;
    };
  }
  
negative.code: 
  assert elem variant [ null "cpp" "pcre16" "pcre32" ];
  
  stdenv.mkDerivation rec {
    pname = "pcre"
      + lib.optionalString (variant == "cpp") "-cpp"
      + lib.optionalString (variant != "cpp" && variant != null) variant;
    version = "8.44";
  
    src = fetchurl {
      url = "mirror://sourceforge/project/pcre/pcre/${version}/pcre-${version}.tar.bz2";
  