anchor.diff:        (pkg: pkg != null && lib.versionAtLeast (lib.getVersion pkg) "1.0")
         [ gstreamer gst-plugins-base gst-plugins-good gst-plugins-bad ];
   in
  -  assert enableGstPlugin -> lib.all (pkg: pkg != null) [ gstreamer gst-plugins-base gst-plugins-good gst-plugins-bad ];
     assert enableViewer -> enableGstPlugin;
  -  assert enableViewer -> libnotify != null;
  -  assert enableViewer -> gnome != null;
  -  assert enableViewer -> gtk3 != null;
     assert enableViewer -> gstreamerAtLeastVersion1;
   
     stdenv.mkDerivation rec {
  
positive.code: { lib, stdenv, fetchFromGitHub, autoreconfHook, pkg-config, gtk-doc, intltool
  , audit, glib, libusb1, libxml2
  , wrapGAppsHook
  , gstreamer ? null
  , gst-plugins-base ? null
  , gst-plugins-good ? null
  , gst-plugins-bad ? null
  , libnotify ? null
  , gnome ? null
  , gtk3 ? null
  , enableUsb ? true
  , enablePacketSocket ? true
  , enableViewer ? true
  
negative.code:       platforms = lib.platforms.unix;
      };
    }
  