Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Update bmake glue for the BIND 9.4.1 import.

This includes a return to building with threads, since one of the
major focuses of the 9.4.x branch is to improve thread performance.

Reimplementation of world/kernel build options. For details, see:

http://lists.freebsd.org/pipermail/freebsd-current/2006-March/061725.html

The src.conf(5) manpage is to follow in a few days.

Brought to you by: imp, jhb, kris, phk, ru (all bugs are mine)

Finish the removal of threads support in ../config.mk,v 1.15.

Fix the WANT_BIND_LIBS knob by correctly spelling it as WITH_BIND_LIBS
to match how similar syntax is used in the ports system. Thanks to kris
for pointing out my mistake here.

Install the lwres library unless the user defines NO_BIND, or the new
knob, NO_BIND_LIBS_LWRES. There is at least one potential customer
for this library in the wings. Thanks to nectar for the reminder.

Don't expose BIND libraries and their headers to the public by default,
but have a knob (WANT_BIND_LIBS) to build and install them in /usr/lib
and /usr/include. Rumors are that this may be useful at a later point,
let's see.

What this really means is that all BIND libraries are now internal to
buildworld (by default, unless WANT_BIND_LIBS is defined), and linked
statically into various BIND executables.

While here, removed redundant -I's from CFLAGS in lib/bind makefiles.

Sponsored by: des
OK'ed by: dougb

Clean up and comment config.mk. Centralize more stuff. Bitch if
POSIX threads libraries are not available. Add crypto support if
the crypto libraries are available. Build dnssec-{keygen,signzone}
if crypto is available.

Submitted by: (in part) dougb@

Switch from BIND 8 to BIND 9.

Submitted by: (in part) dougb@, trhodes@
Reviewed by: dougb@, trhodes@, re@
MFC after: 5 days