i915 driver - enable opregion handle; program CADL.

add opregion handling for drm2 - which exposes some ACPI video configuration
pieces that some Lenovo laptop models use to flesh out which video device
to speak to.  This enables the brightness control in ACPI to work these models.

The CADL bits are also important - it's used to figure out which ACPI
events to hook the brightness buttons into.  It doesn't yet seem to work
for me, but it does for the OP.

Tested:

* Lenovo X230 (mine)
* OP: ASUS UX51VZ

PR:	190186
Submitted by:	Henry Hu <henry.hu.sh@gmail.com>
Reviewed by:	dumbbell
Allow it to compile again.
Fix a typo to catch correct condition.
Fix "make checkdpadd" for lib/libc when MK_SSP != no

Add LIBSSP_NONSHARED to bsd.libnames.mk and append LIBSSP_NONSHARED to DPADD in
lib/libc when MK_SSP != no

Approved by: rpaulo (mentor)
MFC after: 3 days
Phabric: D675 (as part of a larger diff)
PR: 192728
Update these to make them actually compile!

Tested:

* cross compilation to MIPS
Since the size of GPT entry may differ from the sizeof(struct gpt_ent),
use the size from GPT header to iterate entries.

Suggested by:	marcel@
MFC after:	1 week
The standard we compile libc++ with is called c++11 not c++0x.
drm/i915: Add opt_acpi.h and acpi_if.h to the source files

While here, sort the list of generated source files.
drm/i915: Disable the build of i915 on PC98

This module is of no use on this platform and now, i915 depends on ACPI
anyway.

Suggested by:	nyan@
vt(4): Take font offset into account in vt_is_cursor_in_area()

This fixes a "General protection fault" in vt_vga, where
vt_is_cursor_in_area() erroneously reported that the cursor was over the
text. This led to negative integers stored in "unsigned int" and chaos.

MFC after:	1 week
Rather than using an hardcoded reclaim age, rely on an LRU-like approach
for dirhash cache, setting a target percent to reclaim (exposed via
SYSCTL). This allows to always make some amount of progress keeping the maximum
reclaim age dynamic.

Tested by:      pho
Reviewed by:	jhb
vt(4): The cursor coordinates are relative to the drawn area

... not the whole screen. Don't use font offsets in
vt_mark_mouse_position_as_dirty().

This fixes a bug where the mouse position wasn't marked as dirty when
approaching the borders of the drawn area.

MFC after:	1 week
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