[mythtv] r25571 broken compile on Mac OS X 10.5.8?

[David Morrison]

Has anyone else tried compiling r25571 on OSX 10.5.8?  In my case it
fails with the following:

privatedecoder_vda.cpp: In member function 'virtual bool
PrivateDecoderVDA::Init(const QString&, bool, AVCodecContext*)':
privatedecoder_vda.cpp:206: error:
'kCVPixelBufferIOSurfacePropertiesKey' was not declared in this scope