Remove redundant redeclarations of uart_s3c2410_class in
sys/arm/s3c2xx0/uart_bus_s3c2410.c and uart_cpu_s3c2410.c, to silence
two gcc warnings.

Approved by:	re (gjb)
X-MFC-With:	r252394
Make the error handling more consistant.  Shouldn't make any functional
difference.

Approved by:	re (gjb)
Sponsored by:	FreeBSD Foundation
Revert r256095, r256120 (partial), r256121:

r256095:
 - Add gnu/usr.bin/rcs back to the base system.

r256120:
 - Add WITHOUT_RCS back to src.conf.5.

r256121:
 - Remove UPDATING entry regarding gnu/usr.bin/rcs removal.

Requested by:	many
Approved by:	re (marius)
Discussed with:	core
Initialize a variable in sys/contrib/ipfilter/netinet/ip_rcmd_pxy.c, to
silence a gcc warning.

Approved by:	re (gjb)
X-MFC-With:	r255332
Update the Intel igb driver to version 2.4.0
  - This version has support for the new Intel Avoton systems,
including 2.5Gb support, further it now has IPv6/TSO6 support as
well. Shared code has been updated where necessary as well. Thanks
to my new assistant Eric Joyner for doing the transmit path changes
to bring in the IPv6/TSO6 support. Thanks to Gleb for catching the
one bug and change needed in NETMAP.

Approved by: re
Remove no longer useful debugging output and a stale comment.

Approved by:	re (gjb)
Sponsored by:	FreeBSD Foundation