anchor.diff:      + optionalString withTcl "--enable-tcl --with-tcl=${tcl}/lib "
       + optionalString withCyrus "--enable-cyrus ";
   
  -  meta = {
  +  meta = with stdenv.lib; {
       description = "Advanced IRC bouncer";
       homepage = http://wiki.znc.in/ZNC;
  -    maintainers = [ stdenv.lib.maintainers.viric ];
  -    license = "ASL2.0";
  -    platforms = stdenv.lib.platforms.unix;
  +    maintainers = with maintainers; [ viric ];
  +    license = licenses.asl20;
  +    platforms = platforms.unix;
     };
   }
  
positive.code: 
  with stdenv.lib;
  stdenv.mkDerivation rec {
    name = "znc-1.0";
    src = fetchurl {
      url = "http://znc.in/releases/${name}.tar.gz";
      sha256 = "0ah6890ngvj97kah3x7fd8yzi6dpdgrxw1b2skj2cyv98bd3jmd8";
    };
  
    buildInputs = [ openssl pkgconfig ]
  
negative.code: { stdenv, fetchurl, openssl, pkgconfig
  , withPerl ? false, perl
  , withPython ? false, python3
  , withTcl ? false, tcl
  