API changes, most recent first:
+2012-xx-xx - xxxxxxx - lavu 52.2.0 - audioconvert.h
+ Rename audioconvert.h to channel_layout.h. audioconvert.h is now deprecated.
+
2012-xx-xx - xxxxxxx - lavu 52.1.0 - intmath.h
Add av_ctz() for trailing zero bit count