anchor.diff:  
     src = fetchurl {
       url = "https://fedorahosted.org/releases/l/i/libaio/${name}.tar.gz";
  +    multihash = "QmPxxZxeCD1Dmgkbtr8DFwyBDEU7tY9E7cpP2tXVWJAedE";
       sha256 = "0zjzfkwd1kdvq6zpawhzisv7qbq1ffs343i5fs9p498pcf7046g0";
     };
   
  
positive.code: { stdenv
  , fetchurl
  }:
  
  stdenv.mkDerivation rec {
  
negative.code:     makeFlagsArray+=("prefix=$out")
    '';
  
    meta = with lib; {
      description = "Library for asynchronous I/O in Linux";
      homepage = http://lse.sourceforge.net/io/aio.html;
      license = licenses.lgpl21;
  