vt(4): Store a rectangle for the drawable area, not just the top-left corner

This allows backends to verify they do not draw outside of this area.
This fixes a bug in vt_vga where the text was happily drawn over the
right and bottom margins, when using the Gallant font.

MFC after:	1 week
vt(4): Intialize drawable area rectangle each time a font is loaded

This also fixes a problem where early in boot, the area was zero,
leading to nothing displayed for a few seconds.

MFC after:	1 week
vt_vga: Use Write Mode 0 to draw group of 8 pixels using 3 or more colors

This replaces the method based on Write Mode 3, which required reads
from the video memory to load the latches.

MFC after:	1 week
Fix typo: s/mac_rev/mac_ver/

Submitted by:	Stefan Sperling <stsp at openbsd dot org>
Add references to vt(4) and the configuration files in /usr7share/vt where
appropriate (i.e. where syscons was already mentioned and vt supports the
feature). Comments in defaults/rc.conf are updated to match the contents
of the modified man-page rc.conf(5).

Reviewed by:	pluknet, emaste
MFC after:	3 days
Fix up races with f_seqcount handling.

It was possible that the kernel would overwrite user-supplied hint.

Abuse vnode lock for this purpose.

In collaboration with: kib
MFC after:	1 week
Fix "make checkdpadd" by "spoofing" DPADD

Approved by: jmmv (mentor)
Phabric: D631
PR: 192769
Convert LIBCURSES to LIBNCURSES to fix "make checkdpadd"

Also, add a missing LIBPANEL dependency for lldb

Approved by: rpaulo (mentor)
Suggested by: brooks
MFC after: 5 days
Phabric: D675 (as part of a larger diff)
PR: 192762
Introduce missing definition for LIBTERMCAPW

Some Makefiles expect this value to exist

Approved by: rpaulo (mentor)
MFC after: 5 days
Phabric: D675 (as part of a larger diff)
PR: 192762
Remove band.aid that made kbdcontrol lookup keymap files in the syscons
path even under vt, which is no longer useful, since the syscons keymap
files have been converted and committed for use by vt.
Update man-pages to correctly refer to changed pathes and naming conventions
for systems with vt(4) consoles.

MFC after:	3 days
More man pages that need to know about vt in addition to syscons.

MFC after:	3 dayS
Missed comma.
Back-out the references to vt(4) from this man-page. It appears that the
splash support in vt is implemented within the vt driver and does not
depend on splash(4).

Submitted by:	marius@alchemy.franken.de
Remove leading '/' from hardlink name when removing them from the
regular file name. This fixes the problem, when bsdtar can not create
hardlinks to extracted files.

Silence from:	kientzle@
MFC after:	1 week
Sponsored by:	Yandex LLC
- Remove socket file operations declaration from sys/file.h.
- Make them static in sys_socket.c.
- Provide generic invfo_truncate() instead of soo_truncate().

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
Back in the days when the kernel was single threaded, testing
"vm_paging_target() > 0" was a reasonable way of determining if the
inactive queue scan met its target.  However, now that other threads
can be allocating pages while the inactive queue scan is running, it's
an unreliable method.  The effect of it being unreliable is that we
can start swapping out processes when we didn't intend to.

This issue has existed since the kernel was multithreaded, but the
changes to the inactive queue target in 10.0-RELEASE have made its
effects visible.

This change introduces a more direct method for determining if the
inactive queue scan met its target that is not affected by the actions
of other threads.

Reported by:	Steve Polyack
Tested by:	pho, Steve Polyack (an earlier version)
MFC after:	1 week
Sponsored by:	EMC / Isilon Storage Division
vt(4): When creating a window buffer, fill it entirely

... not just the visible part.

This fixes a bug where, when switching from eg. vt_vga to vt_fb (ie. the
resolution goes up), the originally hidden, uninitialized area of the
buffer is displayed on the screen. This leads to a missing text cursor
when it's over an unitialized area.

This was also visible when selecting text: the uninitialized area was
not highlighted.

Internally, this area was zeroed: characters were all 0x00000000,
meaning the foreground and background color was black. Now, everything
is filled with a space with a gray foreground color, like the visible
area.

While here, remove the check for the mute flag and always use
TERMINAL_NORM_ATTR as the character attribute (ie. gray foreground,
black background).

MFC after:	1 week
Add gnugrep.1 to CLEANFILES.

MFC after:	3 days
Sponsored by:	The FreeBSD Foundation
Add host.1 to CLEANFILES.

MFC after:	3 days
X-MFC-To:	stable/10 only
Sponsored by:	The FreeBSD Foundation