anchor.diff:      name = "dropbox-${version}.tar.gz";
       # using version-specific URL so if the version is no longer available,
       # build will fail without having to finish downloading first
  -    # url = "http://www.dropbox.com/download?plat=lnx.x86_64";
  -    url = "http://dl-web.dropbox.com/u/17/dropbox-lnx.x86_64-${version}.tar.gz";
  +    # url = "http://www.dropbox.com/download?plat=lnx.${arch}";
  +    url = "http://dl-web.dropbox.com/u/17/dropbox-lnx.${arch}-${version}.tar.gz";
       inherit sha256;
     };
   
  
positive.code:     ensureDir "$out/bin"
      ln -s "$out/${appdir}/dropbox" "$out/bin/dropbox"
  
      patchelf --set-interpreter ${stdenv.glibc}/lib/ld-linux-x86-64.so.2 \
        "$out/${appdir}/dropbox"
  
      RPATH=${ldpath}:${gcc.gcc}/lib64:$out/${appdir}
      echo "updating rpaths to: $RPATH"
      find "$out/${appdir}" -type f -a -perm +0100 \
        -print -exec patchelf --force-rpath --set-rpath "$RPATH" {} \;
  
negative.code: # replace these libraries with the appropriate ones in
  # nixpkgs.
  
  let
    arch = if stdenv.system == "x86_64-linux" then "x86_64"
      else if stdenv.system == "i686-linux" then "x86"
      else throw "Dropbox client for: ${stdenv.system} not supported!";
      
    interpreter = if stdenv.system == "x86_64-linux" then "ld-linux-x86-64.so.2"
      else if stdenv.system == "i686-linux" then "ld-linux.so.2"
      else throw "Dropbox client for: ${stdenv.system} not supported!";
  
    version = "1.4.21";
    sha256 = if stdenv.system == "x86_64-linux" then "94073842f4a81feee80bca590e1df73fc3cab47ba879407ceba2de48f30d84e2"
      else if stdenv.system == "i686-linux" then "121v92m20l73xjmzng3vmcp4zsp9mlbcfia73f5py5y74kndb2ap"
      else throw "Dropbox client for: ${stdenv.system} not supported!";
  
    # relative location where the dropbox libraries are stored
    appdir = "opt/dropbox";
  