- 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

Eliminate 19 warnings in libc (at level WARNS=2) of the
`implicit declaration of function' variety.

Add awareness of an IPv6.

MFC after: 1 week

Quoting log message for OpenBSD rev 1.7:
``Tack on MagniComp (BSD) license since this originally came from rdist.''

Obtained from: OpenBSD

- Put missing prototype for rcmd() in <unistd.h>.
- Clean up the manpage.
- style(9) rcmdsh.c.

Committed from: BSDCon/EU 2k+1 terminal room

Allow users to specify a command to use as remote command instead of
using rcmd directly. This has been in my tree for a long time, but we
may need to sync with OpenBSD before MFC.

Obtained from: openbsd
PR: 15830

MFC after: 2 months