OK, the pending abs() disaster has hit:

drivers/usb/class/audio.c:404: warning: static declaration of 'abs' follows non-static declaration

This is due to the declaration in kernel.h.  AFAIK there's not even a matching
definition for that.

The patch implements abs() as a macro in kernel.h and kills off various
private implementations.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>