anchor.diff:    buildInputs = [
       cups
       libusb
  +    libxml2
     ];
  -
  -  phases = [ "unpackPhase" "installPhase" "fixupPhase" ];
   
     installPhase = ''
   
  
positive.code:   '';
  
    preFixup = ''
  
    for bin in $out/bin/*; do
      patchelf --set-interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" "$bin"
      patchelf --set-rpath "$out/lib:${stdenv.lib.getLib cups}/lib" "$bin"
    done
  
    patchelf --set-rpath "$out/lib:${stdenv.lib.getLib cups}/lib" "$out/lib/libscmssc.so"
  
    ln -s ${stdenv.cc.cc.lib}/lib/libstdc++.so.6 $out/lib/
  
    '';
  
    # all binaries are already stripped
  
negative.code: { stdenv, fetchurl, glibc, cups, libusb, libxml2, ghostscript }:
  
  let
  
  