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)

Second-to-last commit implementing Capsicum capabilities in the FreeBSD
kernel for FreeBSD 9.0:

Add a new capability mask argument to fget(9) and friends, allowing system
call code to declare what capabilities are required when an integer file
descriptor is converted into an in-kernel struct file *. With options
CAPABILITIES compiled into the kernel, this enforces capability
protection; without, this change is effectively a no-op.

Some cases require special handling, such as mmap(2), which must preserve
information about the maximum rights at the time of mapping in the memory
map so that they can later be enforced in mprotect(2) -- this is done by
narrowing the rights in the existing max_protection field used for similar
purposes with file permissions.

In namei(9), we assert that the code is not reached from within capability
mode, as we're not yet ready to enforce namespace capabilities there.
This will follow in a later commit.

Update two capability names: CAP_EVENT and CAP_KEVENT become
CAP_POST_KEVENT and CAP_POLL_KEVENT to more accurately indicate what they
represent.

Approved by: re (bz)
Submitted by: jonathan
Sponsored by: Google Inc

On amd64 platform, use linux32 headers so 32-bit Linux applications
would be able to work with aac(4).

This approach is used by some other drivers as well. However, we
need a more generic way to do this in order to avoid having to
special case headers in individual drivers for each platform.

Obtained from: Adaptec (version b11518)
Approved by: scottl

Add missing <sys/module.h> includes

Use __FBSDID().
Also some minor style cleanups.

The AAC_COMPAT_LINUX option was really annoying, since it made the
aac driver dependent on the linux emulation module. This was
especially bad for the release engineers who tried to move the
aac driver from the kernel onto the drivers floppy. The linux
compat bits for this driver are now in their own driver, aac_linux.
It can be loaded as a module or compiled into the kernel. For
the latter case, the AAC_COMPAT_LINUX option is needed, along with
the COMPAT_LINUX option.

I've tested this in every configuration I can think of. This is an
MFC candidate for 4.7.

Idea from: rwatson
MFC after: 3 days