[distcc] Higher compression

[Matias D'Ambrosio]

> I think linking to the system bz2 shouldn't be a problem.  Though we
> should use autoconf to make sure distcc still builds on machines
> without bz2, and it'll need ifdefs to accommodate that - though not
> too many if it's reasonably clean.  Also, we must remember testing and
> documentation of the change.
 I have just finished a first test run, I compiled distcc using distcc both 
with lzo and bz2, it took 1m 50s with bz2 and 3m 11s with lzo, so the benefit 
is obvious in bandwidth limited cases like mine.
 I have #ifdef'ed around all the code, and later I'll see if I can find the 
proper way to modify the build scripts (I just modified config.h after 
running ./configure ). I have to polish the comments a bit, documentation 
wise there isn't much, just a new option (bz2) which at this time is mutually 
exclusive with lzo, and I created a new protocol version (3). I did my best 
to keep the code as close to the lzo code as possible,  a great deal of it 
was just copy and paste.