anchor.diff:      (mkFlag (libbluray != null) "1.0" "libbluray")
       (mkFlag (libbs2b != null) "2.3" "libbs2b")
       (mkFlag (libcaca != null) "1.0" "libcaca")
  -    #(mkFlag (cdio-paranoia != null) "0.9" "libcdio")
  -    (mkFlag (libdc1394 != null && libraw1394 != null) "0.5" "libdc1394")
  +    #(mkFlag (cdio-paranoia != null && gplLicensing) "0.9" "libcdio")
  +    (mkFlag (if !isLinux then false else libdc1394 != null && libraw1394 != null && isLinux) "0.5" "libdc1394")
       (mkFlag (libiconv != null) "1.2" "iconv")
  -    #(mkFlag (libiec61883 != null && libavc1394 != null && libraw1394 != null) "1.0" "libiec61883")
  +    #(mkFlag (if !isLinux then false else libiec61883 != null && libavc1394 != null && libraw1394 != null) "1.0" "libiec61883")
       #(mkFlag (libmfx != null) "2.6" "libmfx")
  -    (mkFlag (libmodplug != null) "0.9" "libmodplug")
  +    (mkFlag (disDarwinFix (libmodplug != null)) "0.9" "libmodplug")
       #(mkFlag (libnut != null) "0.5" "libnut")
       (mkFlag (libopus != null) "1.0" "libopus")
  -    (mkFlag (libssh != null) "2.1" "libssh")
  +    (mkFlag (disDarwinFix (libssh != null)) "2.1" "libssh")
       (mkFlag (libtheora != null) "0.5" "libtheora")
  -    (mkFlag (libva != null) "0.6" "vaapi")
  +    (mkFlag (if isDarwin then false else libva != null) "0.6" "vaapi")
       (mkFlag (libvdpau != null) "0.5" "vdpau")
       (mkFlag (libvorbis != null) "0.5" "libvorbis")
  -    (mkFlag (libvpx != null) "0.6" "libvpx")
  +    (mkFlag (disDarwinFix (libvpx != null)) "0.6" "libvpx")
       (mkFlag (libwebp != null) "2.2" "libwebp")
       (mkFlag (libX11 != null && libXv != null) "2.3" "xlib")
       (mkFlag (libxcb != null) "2.5" "libxcb")
  
positive.code:  *
   * Packages with errors:
   *   flite ilbc schroedinger
   *
   * Not packaged:
   *   aacplus avisynth cdio-paranoia crystalhd libavc1394 libiec61883
   *   libmxf libnut libquvi nvenc opencl opencore-amr openh264 oss shine twolame
   *   utvideo vo-aacenc vo-amrwbenc xvmc zvbi blackmagic-design-desktop-video
   *
   * Not supported:
   *   stagehright-h264(android only)
   *
   * Known issues:
   * 0.5     - libgsm: configure fails to find library (fix: disable for 0.5)
  
negative.code:   # Flag change between versions (e.g. "--enable-armvfp" -> "--enable-vfp" changed in v1.1)
    chgFlg = chgVer: oldFlag: newFlag: if reqMin chgVer then newFlag else oldFlag;
  
    # Disable dependency that needs fixes before it will work on Darwin
    disDarwinFix = origArg: if stdenv.isDarwin then false else origArg;
  
    isCygwin = stdenv.isCygwin;
    isDarwin = stdenv.isDarwin;
    isLinux = stdenv.isLinux;
  in
  
  /*
  