Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Port lastlogin(8) to utmpx.

While there, fix a bug I introduced previously. We must reopen the
database for each username passed on the command line. We must rewind
the database and search from the beginning.

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

Port lastlogin(1) to libulog.

Just use ulog_getutxuser() to obtain lastlog records or ulog_getutxent()
to browse through all of them.

Perform a major cleanup of the usr.sbin Makefiles.
These are not perfectly in agreement with each other style-wise, but they
are orders of orders of magnitude more consistent style-wise than before.

Set WARNS=2 on programs that compile cleanly with it; add $FreeBSD$
where necessary.

Submitted by: Mike Barcroft <mike@q9media.com>

- Backout botched attempt to introduce MANSECT feature.
- MAN[1-9] -> MAN.

Set the default manual section for usr.sbin/ to 8.

Added the lastlogin utility.

Obtained from: NetBSD