anchor.diff:  { stdenv, fetchurl, fetchpatch, python, zlib, pkgconfig, glib
  -, ncurses, perl, pixman, vde2, alsaLib, texinfo, flex
  +, perl, pixman, vde2, alsaLib, texinfo, flex
   , bison, lzo, snappy, libaio, gnutls, nettle, curl
   , makeWrapper
   , attr, libcap, libcap_ng
  
positive.code:   nativeBuildInputs = [ python python.pkgs.sphinx pkgconfig flex bison ]
      ++ optionals gtkSupport [ wrapGAppsHook ];
    buildInputs =
      [ zlib glib ncurses perl pixman
        vde2 texinfo makeWrapper lzo snappy
        gnutls nettle curl
      ]
      ++ optionals stdenv.isDarwin [ CoreServices Cocoa Hypervisor rez setfile ]
      ++ optionals seccompSupport [ libseccomp ]
      ++ optionals numaSupport [ numactl ]
  
negative.code: , vncSupport ? !nixosTestRunner, libjpeg, libpng
  , smartcardSupport ? !nixosTestRunner, libcacard
  , spiceSupport ? !stdenv.isDarwin && !nixosTestRunner, spice, spice-protocol
  , ncursesSupport ? !nixosTestRunner, ncurses
  , usbredirSupport ? spiceSupport, usbredir
  , xenSupport ? false, xen
  , cephSupport ? false, ceph
  