anchor.diff:      "--with-macvtap"
       "--with-virtualport"
       "--with-init-script=systemd+redhat"
  +    "--with-storage-disk"
       "--with-storage-zfs"
     ] ++ optionals stdenv.isDarwin [
       "--with-init-script=none"
  
positive.code:     substituteInPlace $out/libexec/libvirt-guests.sh \
        --replace "$out/bin" "${gettext}/bin" \
        --replace "lock/subsys" "lock"
      rm $out/lib/systemd/system/{virtlockd,virtlogd}.*
    '' + optionalString stdenv.isLinux ''
      wrapProgram $out/sbin/libvirtd \
        --prefix PATH : ${makeBinPath [ iptables iproute pmutils numad numactl ]}
    '';
  
negative.code:   nativeBuildInputs = [ makeWrapper pkgconfig ];
    buildInputs = [
      libxml2 gnutls perl python2 readline gettext libtasn1 libgcrypt yajl
      libxslt xhtml1 perlPackages.XMLXPath curl libpcap
    ] ++ optionals stdenv.isLinux [
      libpciaccess devicemapper lvm2 utillinux systemd libnl numad zfs
      libapparmor libcap_ng numactl xen attr parted
    ] ++ optionals stdenv.isDarwin [
       libiconv gmp
    ];
  