twa(4): Request a bus scan after attaching the driver to CAM.

Our CAM doesn't (yet) do this by default.

This fixes disk detection upon kldload.

Taken-from: FreeBSD (which has since moved it to CAM).

While here, add a cam_simq_release() I forgot and remove a comment that
does not apply to us.
twa(4): Remove an extra : in a message (it will be automatically added).
kernel/amrp: Add a missing dependency.
Bring in the config_intrhook(9) manual page from FreeBSD.
amr(4): Remove some old code.
amr(4): Remove unused code.
<sys/kernel.h>: Remove unused sysinit id.
config_intrhook.9: Update struct intr_config_hook to ours.
kernel: Add descriptions to the intrhooks that miss them.

The description is printed in the

"**WARNING** waiting for the following device to finish configuring: ..."

messages we occasionally see, from run_interrupt_driven_config_hooks(),
most of the times for xpt.

Some of them had been accidentally removed in past synchronizations with
FreeBSD (mostly by me).
ld/gold: Add link-time optimization plugin support

The binutils 2.22 ld.bfd and ld.gold linkers were not configured to support
link-time optimization plugins (-plugin switch) previously.  This changeset
adds -plugin support to both linkers.  The ld.bfd linker was previously
built statically, but it was necessary to change this to use the libc and
libz shared libraries because the -plugin option requires the dynamic
function dlopen().

The same update was not applied to binutils 2.21 linkers.
Libc: Remove i386 gcc hack concerning popcountsi2

Ref: 0cfd7e44b3676f6a43164acab0aaea46365b5c53
Ref: 4b548429247a10382073a0c227af306272160d8d

Back in Oct 2010, a "horrible hack" was added to libc in order to fix a
Firefox bug concerning a late dynamic link of a libcairo.so.2 symbol.  A
weak reference to popcountsi2 was added to i386 libc in order to force it
to be available.

Up through gcc 4.6, this hack worked because the symbol is global in the
libgcc.a library, but it's a hidden symbol starting with the gcc 4.7
version of libgcc.a.  This causes a build failure on bin/rmail while
building world with gcc 4.7.

Since Oct 2010, rtld has undergone significant changes.
With the hope that the issue is obsolete, the hack is being removed.
This allows gcc 4.7 to compile DragonFly world and kernel source.
We'll have to track firefox manually to verify the issue the hack fixed
doesn't return.
CCVER: Add /usr/pkgsrc/lang/gcc-aux as 'gcc47'

There are two gcc-4.7.x packages in pkgsrc that will build gcc 4.7-based
compilers on Dragonfly.  One is located at lang/gcc47 and the other is
located at lang/gcc-aux.  Both have been patched by myself, but gcc-aux
seems to work better, especially with regards to link-time optimization.

Consequently, a new valid value for CCVER has been created, "gcc47", which
references lang/gcc-aux while building world and kernel.  Both will
compile, and the produced kernel will boot, but there are some network
issues.  Consequently, CCVER=gcc47 should only be used by developers who
have the express intent to fix any issues the arise from compiling
DragonFly sources with the latest GCC compiler.  Normal users looking
for non-base GCC compilers should stick with CCVER=gcc46 for now.
Import libpcap-1.3.0.

See CHANGES for the details.
Import tcpdump-4.3.0.

See CHANGES for details.
Merge branch 'vendor/LIBPCAP'
Merge branch 'vendor/TCPDUMP'
Update files for libpcap-1.3.0 and tcpdump-4.3.0 imports.
kernel - Fix missing lock in pbuf update (minor)

* Fix a small timing window in an update of a counter.

* This bug is not known to have been hit by anyone, due to default
  settings for asynchronous I/O.
Import libarchive-3.0.4.
Merge branch 'vendor/LIBARCHIVE'