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

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

MFC r260334:

Split the last gcc-specific flags off into CFLAGS.gcc. This also
removes the need to use -Qunused-arguments for clang throughout the
tree.

MFC r260369:

Apply band-aid for 32-bit compat libs failures after r260334: put back
-Qunused-arguments for clang for now, until I can figure out a way to
make it unneeded in all scenarios. Sorry about the breakage.

MFC r251516

Implement foreign device handling.

PR: kern/172091

MFC r249257:
Add support for getting and setting BBU properties related to battery
relearning. Specifically, add subcommands to mfiutil(8) which allow the
user to set the BBU and autolearn modes when the firmware supports it,
and add a subcommand which kicks off a battery relearn.

MFC r249258:
Switch to a 2-clause license.

MFC r237259 r237260 r237329:
Allow users with RO privilege to the device to read the RO attributes. [0]
Add __unused macros to appropriate places in order to allow building
with WARNS=6 on base gcc, gcc46, and clang

PR: bin/167302 [0]
Approved by: cperciva (implicit)

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

Approved by: re (implicit)

Fixed dependencies (make checkdpadd).

Move mfiutil.1 to mfiutil.8 for consistency. Remove superfulous README.

Approved by: re

ntroduce mfiutil, a basic utility for managing LSI SAS-RAID & Dell PERC5/6
controllers. Controller, array, and drive status can be checked, basic
attributes can be changed, and arrays and spares can be created and deleted.
Controller firmware can also be flashed.

This does not replace MegaCLI, found in ports, as that is officially sanctioned
and supported by LSI and includes vastly more functionality. However, mfiutil
is open source and guaranteed to provide basic functionality, which can be
especially useful if you have a problem and can't get MegaCLI to work.

Approved by: re
Obtained from: Yahoo! Inc.