anchor.diff:    ] ++ optional openglExtlib libGLU_combined
       ++ optionals nonfreeLicensing [ fdk_aac openssl ]
       ++ optional ((isLinux || isFreeBSD) && libva != null) libva
  +    ++ optional (libvmaf != null  && version3Licensing ) libvmaf
       ++ optionals isLinux [ alsaLib libraw1394 libv4l ]
       ++ optional (isLinux && !isAarch64 && libmfx != null) libmfx
       ++ optional nvenc nv-codec-headers
  
positive.code:  *  Licensing options (yes some are listed twice, filters and such are not listed)
   */
  , gplLicensing ? true # GPL: fdkaac,openssl,frei0r,cdio,samba,utvideo,vidstab,x265,x265,xavs,avid,zvbi,x11grab
  , version3Licensing ? true # (L)GPL3: opencore-amrnb,opencore-amrwb,samba,vo-aacenc,vo-amrwbenc
  , nonfreeLicensing ? false # NONFREE: openssl,fdkaac,blackmagic-design-desktop-video
  /*
   *  Build options
  
negative.code:     (enableFeature ((isLinux || isFreeBSD) && libva != null) "vaapi")
      (enableFeature (libvdpau != null) "vdpau")
      (enableFeature (libvorbis != null) "libvorbis")
      (enableFeature (libvmaf != null && version3Licensing) "libvmaf")
      (enableFeature (libvpx != null) "libvpx")
      (enableFeature (libwebp != null) "libwebp")
      (enableFeature (libX11 != null && libXv != null && libXext != null) "xlib")
  