- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

The last big commit: let usr.sbin/ use WARNS=6 by default.

Remove unnecessary SRCS= where could be guessed directly by our
bsd.*.mk infrasture.

Obtained from: ru

Add dumb console driver and related bits.

dcons(4): very simple console and gdb port driver
dcons_crom(4): FireWire attachment
dconschat(8): User interface to dcons

Tested with: i386, i386-PAE, and sparc64.