HEADS UP: dynamic root support now in the tree

I just got through with my commit spree to enable users to build /bin
and /sbin dynamically linked. To do this required a fair amount of
tweaking and moving around libraries and such dangerous equipment as
rtld-elf. If you have any systems that you are dearly in love with,
now is not the time to cvsup. Please wait until any potential issues
are shaken out of the tree. I've done as much testing as I can, but
as experience has shown me, there are likely to be issues.

IA64 users (both of you), do not attempt to build the world using
WITH_DYNAMICROOT! This is guaranteed to fail! I'm currently working
on getting ahold of a toolchain expert to work out the one outstanding
issue with this platform.

Thank you for being patient and please follow up with me if there are
*any* issues. There is a huge potential for foot-shooting here that I
hope to have mitigated but it is possible that I might have missed
something.

Now that all the grim stuff is out of the way, a couple of nice
benefits to building your world WITH_DYNAMICROOT:

1) Space savings. A statically linked /bin and /sbin is 32 MB on
   i386. A dynamically linked /bin and /sbin is only 12 MB (including
   /lib, /libexec, and /rescue)

2) NSS support. You are now able to use a dynamically loaded nss
   module for passwd and group maps and have things like ls(1) and
   tcsh(1) grok uids and gids coming from those sources.

-gordon