anchor.diff:      wayland
     ];
   
  -  configureFlags = [
  -    "--disable-maintainer-mode"
  -    "--disable-fatal-warnings"
  -    "--disable-extra-checks"
  -    "--disable-debug"
  -    "--disable-examples"
  -    "--enable-encoders"
  -    "--${boolEn (libdrm != null)}-drm"
  -    "--${boolEn (libx11 != null)}-x11"
  -    "--${boolEn opengl-dummy.glx}-glx"
  -    "--${boolEn (wayland != null)}-wayland"
  -    "--${boolEn opengl-dummy.egl}-egl"
  -    "--disable-gtk-doc"
  -    "--disable-gtk-doc-html"
  -    "--disable-gtk-doc-pdf"
  -    "--enable-gobject-cast-checks"
  -    "--disable-glib-asserts"
  -  ];
  -
  -  NIX_CFLAGS_COMPILE = [
  -    "-I${gst-plugins-bad}/include/gstreamer-1.0"
  -    # FIXME: Gstreamer installs gstglconfig.h in the wrong location
  -    "-I${gst-plugins-bad}/lib/gstreamer-1.0/include"
  +  mesonFlags = [
  +    "-Dwith_encoders=yes"
  +    "-Dwith_drm=${boolYn (libdrm != null)}"
  +    "-Dwith_x11=${boolYn (libx11 != null)}"
  +    "-Dwith_glx=${boolYn opengl-dummy.glx}"
  +    "-Dwith_wayland=${boolYn (opengl-dummy.egl && wayland != null)}"
  +    "-Dwith_egl=${boolYn opengl-dummy.egl}"
     ];
   
     postInstall = "rm -rvf $out/share/gtk-doc";
  
positive.code: 
  let
    inherit (lib)
      boolEn
      optionals;
  
    sources = {
  
negative.code: { stdenv
  , fetchurl
  , lib
  , meson
  , ninja
  
  , glib
  , gst-plugins-bad
  