Log Message:
Initial import of pbzip2:

The pbzip2 program is a parallel version of bzip2 for use on shared
memory machines.  It provides near-linear speedup when used on true
multi-processor machines and 5-10% speedup on Hyperthreaded machines.
The output is fully compatible with the regular bzip2 data so any
files created with pbzip2 can be uncompressed by bzip2 and vice-versa.