anchor.diff:  { fetchurl, stdenv, zlib, lzo, libtasn1, nettle
  -, guileBindings, guile, pkgconfig }:
  +, guileBindings, guile, pkgconfig, perl }:
   
   assert guileBindings -> guile != null;
   
  
positive.code:   })];
  
    configurePhase = ''
      ./configure --prefix="$out"                                 \
        --disable-dependency-tracking --enable-fast-install       \
        --with-lzo --with-libtasn1-prefix="${libtasn1}"		\
  
negative.code:         else ""}
    '';
  
    buildInputs = [ zlib lzo libtasn1 pkgconfig perl ]
      ++ stdenv.lib.optional guileBindings guile;
  
    propagatedBuildInputs = [ nettle ];
  