anchor.diff:  , pango
   , wayland
   , xorg
  +
  +, channel ? "1.22"
   }:
   
   let
     inherit (stdenv.lib)
  -    enFlag
  +    boolEn
       optionalString;
  -
  -  versionMajor = "1.22";
  -  versionMinor = "0";
  -  version = "${versionMajor}.${versionMinor}";
   in
  -
   stdenv.mkDerivation rec {
  -  name = "cogl-${version}";
  +  name = "cogl-${channel}.2";
   
     src = fetchurl {
  -    url = "mirror://gnome/sources/cogl/${versionMajor}/${name}.tar.xz";
  -    sha256Url = "mirror://gnome/sources/cogl/${versionMajor}/${name}.sha256sum";
  -    sha256 = "14daxqrid5039xmq9yl4pk86awng1n9zgl6ysblhc4gw2ifzp7b8";
  +    url = "mirror://gnome/sources/cogl/${channel}/${name}.tar.xz";
  +    sha256Url = "mirror://gnome/sources/cogl/${channel}/${name}.sha256sum";
  +    sha256 = "39a718cdb64ea45225a7e94f88dddec1869ab37a21b339ad058a9d898782c00d";
     };
   
     nativeBuildInputs = [
  
positive.code:     #"--enable-emscripten"
      "--disable-standalone"
      "--disable-debug"
      (enFlag "unit-tests" doCheck null)
      (enFlag "cairo" (cairo != null) null)
      "--disable-profile"
      "--disable-maintainer-flags"
      "--enable-deprecated"
      (enFlag "glibtest" (glib != null) null)
      (enFlag "glib" (glib != null) null)
      (enFlag "cogl-pango" (pango != null) null)
      (enFlag "cogl-gst" (gstreamer != null && gst-plugins-base != null) null)
      "--enable-cogl-path"
      (enFlag "gdk-pixbuf" (gdk-pixbuf != null) null)
      "--disable-quartz-image"
      "--disable-examples-install"
      "--enable-gles1"
  
negative.code:     "--disable-gtk-doc-pdf"
      "--enable-nls"
      "--enable-rpath"
      "--${boolEn (gobject-introspection != null)}-introspection"
      "--with-x"
    ];
  
  