anchor.diff:  { stdenv
  +, bc
  +, bind
  +, dhcp
   , fetchurl
   , perl
  -, bc
  -, openssl
  +
  +, boost
  +#, cassandra
  +, googletest
  +, log4cplus
   , mysql_lib
  +, openssl_1-0-2
   , postgresql
  -, log4cplus
  -, boost
  -, googletest
   }:
   
  +let
  +  inherit (stdenv.lib)
  +    optionals;
  +
  +  version = "1.1.0";
  +in
   stdenv.mkDerivation rec {
     name = "kea-${version}";
  -  version = "1.0.0";
   
     src = fetchurl {
       url = "https://ftp.isc.org/isc/kea/${version}/${name}.tar.gz";
  -    sha256 = "1zjs2dbdwa7hk6a2h9dgry64v0985l0sqphisc43s4zr33llz64n";
  +    hashOutput = false;
  +    sha256 = "c3d97aee4faa19653ffe6d37e797e2fbf632124cd0b98bb502f9b97b5a383c2d";
     };
   
     nativeBuildInputs = [
  
positive.code:     "--disable-logger-checks"
    ];
  
    makeFlags = [
      # Spoof libtool since googletest no longer provides libtool files.
      "GTEST_LDADD=${googletest}/lib/libgtest.so"
    ];
  
    CXXFLAGS = "-std=c++11";
  
    preFixup = ''
      sed -i 's,openssl-1.0.0,openssl,g' $out/lib/pkgconfig/dns++.pc
    '';
  
    meta = with stdenv.lib; {
      license = licenses.mpl2;
  
negative.code:   ];
  
    buildInputs = [
      boost
      #cassandra
      log4cplus
      mysql_lib
      openssl_1-0-2
      postgresql
    ];
  
    postPatch = ''
      find . -name \*.in -and -not -name Makefile.in \
        -exec sed -i 's,@abs_top_\(src\|build\)dir@,/no-such-path,g' {} \;
  
      find . -name Makefile.in -exec sed -i '/-D[^ =]*=/s,$(abs_top_\(src\|build\)dir),/no-such-path,g' {} \;
    '';
  
    configureFlags = [
      "--sysconfdir=/etc"
      "--localstatedir=/var"
      "--disable-debug"
      #"--with-werror"
      # Flag is not a boolean
      #"--disable-static-link"
      "--with-pythonpath"
      # Flag is not a boolean
    ] ++ optionals doCheck [
      "--with-gtest-source=${googletest}/src/gtest"
      "--with-gtest=${googletest}"
    ] ++ [
      "--without-lcov"
      "--with-openssl=${openssl_1-0-2}"
      "--without-botan-config"
      "--with-dhcp-mysql=${mysql_lib}/bin/mysql_config"
      "--with-dhcp-pgsql=${postgresql}/bin/pg_config"
      #"--with-cql=${cassandra}/bin/cql_config"
      "--with-log4cplus"
      "--disable-generate-parser"
      "--disable-generate-docs"
  