anchor.diff:      libgcrypt
       libgpg-error
       libksba
  -    libusb
  -    npth
  +    libusb'
  +    pth'
       openldap
       readline
       sqlite
       zlib
  +  ] ++ optionals (versionOlder version "2.1") [
  +    curl
     ];
   
     postPatch = ''
  
positive.code:   ];
  
    version = sources.${channel}.version;
  in
  
  stdenv.mkDerivation rec {
  
negative.code: 
  #, adns
  , bzip2
  , curl
  , gnutls
  , libassuan
  , libgcrypt
  , libgpg-error
  , libksba
  , libusb
  , libusb-compat
  , npth
  , pth
  , openldap
  , pcsclite
  , readline
  