anchor.diff:  
     preFixup = ''
       gappsWrapperArgs+=(--prefix PATH : "${stdenv.lib.makeBinPath [ mtools cdrkit libcdio qemu ]}")
  +  '';
  +
  +  mesonFlags = [
  +    "-Dovirt=false"
  +  ];
  +
  +  postPatch = ''
  +    chmod +x build-aux/post_install.py # patchShebangs requires executable file
  +    patchShebangs build-aux/post_install.py
     '';
   
     passthru = {
  
positive.code:   doCheck = true;
  
    nativeBuildInputs = [
      meson ninja vala pkgconfig gettext wrapGAppsHook gobjectIntrospection desktop-file-utils
    ];
  
    buildInputs = [
  
negative.code: { stdenv, fetchurl, meson, ninja, wrapGAppsHook, pkgconfig, gettext, itstool, libvirt-glib
  , glib, gobjectIntrospection, libxml2, gtk3, gtkvnc, libvirt, spice-gtk
  , spice-protocol, libsoup, libosinfo, systemd, tracker, tracker-miners, vala
  , libcap, yajl, gmp, gdbm, cyrus_sasl, gnome3, librsvg, desktop-file-utils
  