anchor.diff:      license = licenses.zlib;
       platforms = platforms.all;
     };
  -}
  +} // stdenv.lib.optionalAttrs (stdenv.hostPlatform != stdenv.buildPlatform) {
  +  preConfigure = ''
  +    export CHOST=${stdenv.hostPlatform.config}
  +  '';
  +})
  
positive.code:     # what causes this difference.
    + stdenv.lib.optionalString stdenv.hostPlatform.isDarwin ''
      for file in $out/lib/*.so* $out/lib/*.dylib* ; do
        install_name_tool -id "$file" $file
      done
    ''
      # Non-typical naming confuses libtool which then refuses to use zlib's DLL
  
negative.code: , static ? false
  }:
  
  stdenv.mkDerivation (rec {
    name = "zlib-${version}";
    version = "1.2.11";
  
  