Leslie Polzer's enhancements from Google Summer of code 2007

Leslie's enhancements have been available for a long time at
the
repo.or.cz git repository that we used for the Summer of
Code.
However, since that repository contained all his changes
during the
development process but didn't subdivide them by topic, they
were
somewhat hard to keep up to date with respect to the CVS
tree.

I've collected his changes into three aggregated patches,
one per
topic.  These topics are:

1. ARG_MAX related changes, mainly to xargs
2. Rewrite of updatedb as a C program
3. Implmentation of find predicates for querying file
attributes

It's possible that I have accidentally broken somethin
while
re-arranging the patches, but certainly the test suite
passes for each
of them.  I attach the three patches.

Thanks,
James.