anchor.diff:  , libcaca ? null # Textual display (ASCII art)
   #, libcdio-paranoia ? null # Audio CD grabbing
   , libdc1394 ? null, libraw1394 ? null # IIDC-1394 grabbing (ieee 1394)
  +, libdrm ? null # libdrm support
   , libiconv ? null
   #, libiec61883 ? null, libavc1394 ? null # iec61883 (also uses libraw1394)
   , libmfx ? null # Hardware acceleration vis libmfx
  
positive.code:     #(enableFeature (libcaca != null) "libcaca")
      #(enableFeature (cdio-paranoia != null && gplLicensing) "libcdio")
      (enableFeature (if isLinux then libdc1394 != null && libraw1394 != null else false) "libdc1394")
      (enableFeature (libiconv != null) "iconv")
      (enableFeature (libjack2 != null) "libjack")
      #(enableFeature (if isLinux then libiec61883 != null && libavc1394 != null && libraw1394 != null else false) "libiec61883")
  
negative.code:   ] ++ optionals openglExtlib [ libGL libGLU ]
      ++ optionals nonfreeLicensing [ fdk_aac openssl ]
      ++ optional ((isLinux || isFreeBSD) && libva != null) libva
      ++ optional ((isLinux || isFreeBSD) && libdrm != null) libdrm
      ++ optional (!isAarch64 && libvmaf != null && version3Licensing) libvmaf
      ++ optionals isLinux [ alsa-lib libraw1394 libv4l vulkan-loader glslang ]
      ++ optional (isLinux && !isAarch64 && libmfx != null) libmfx
  