anchor.diff:  { stdenv
   , fetchzip
  +, lib
   , makeWrapper
   , perl
   , pkgconfig
  
positive.code:     xorg.libXxf86vm
    ];
  
    postPatch =
      /* https://github.com/mpv-player/mpv/issues/3766
         vdpau configure detection requires a vdpau device to exist.
         This hack replaces the configure test with the test for libdl. */ ''
        sed -i wscript \
          -e 's,libavcodec/vdpau.h,dlfcn.h,' \
          -e "s/.*av_vdpau_bind_context.*/'dlopen\(\"\", 0)',/"
      '';
  
    configureFlags = [
      ###"--enable-cplayer"
  
negative.code:     #"--${boolEn (vapoursynth != null)}-vapoursynth-lazy"
      #"--${boolEn (vapoursynth != null)}-vapoursynth-core"
      "--${boolEn (libarchive != null)}-libarchive"
      "--${boolEn (ffmpeg != null)}-libavdevice"
      "--${boolEn (SDL_2 != null)}-sdl2"
      "--disable-sdl1"
  