[Unix-jun72] build reorg

[Tim Newsham]

I just committed some changes that reorganize the build process a bit.
The Readme contains information about the change.  Basically now you
just do a "make" at the top level.  If you have a checked out tree
you might have to move your current "build" aside when you do an
update.  Please let me know if anyone notices brokenness.

Warren, can you look over the Readme?

Tim Newsham
http://www.thenewsh.com/~newsham/