I'm not sure you understand what I mean.
On SLES 10, all the libs of bzip2 are in the package bzip2 which is included in the basic system.

On SLES 11, the libs of bzip2 have been removed from the package bzip2 and be added in a new package "libbz2-devel" which is not included in the basic system.This is why we need this dependency in SLES 11, and only in SLES 11.