For data and instruction prefetch aborts, call the same handler in the C
code, passing a 0/1 flag that indicates which type of abort it was.  This
sets the stage for unifying the handling of page faults in a single routine.

Submitted by: Svatopluk Kraus <onwahe@gmail.com>,
	      Michal Meloun <meloun@miracle.cz
Add interrupt support for GPIO pins on OMAP4 and AM335x.

This enables the use of GPIO pins as interrupt sources for kernel devices
directly attached to gpiobus (userland notification will be added soon).

The use of gpio interrupts for other kernel devices will be possible when
intrng is complete.

All GPIO pins can be set to trigger on:

- active-low;
- active-high;
- rising edge;
- falling edge.

Tested on:	Beaglebone-black
Use compiled in default keymaps which are available both in syscons and vt.
Fix OLD_LIBS for libxo moved to /lib

Pointed out by: kib
Create the PKG_DIR if it is missing
Add macros for asm barrier instructions with arch-specific implementations.
Define only the CP15 register operations that are valid for the architecture.

Submitted by: Svatopluk Kraus <onwahe@gmail.com>,
              Michal Meloun <meloun@miracle.cz
Deorbit the IEEE-488/GPIB support.
Extern declarations in C files loses compile-time checking that
the functions' calls match their definitions. Move them to header files.

Reviewed by:	jilles (previous version)
Import mandoc 1.13.2
patch: Bring in xstrdup and use it when appropriate.

The function savestr allows NULL return values during Plan A patching so in
case of out of memory conditions, Plan B can step in.  In many cases, NULL
value is not properly handled, so use xstrdup here (it's outside Plan A/B
patching, which means that even Plan B relies on successful operations).

Clean up some whitespaces while here

Obtained from:	OpenBSD
MFC after:	2 weeks
Update mandoc to 1.13.2
mandoc -Tlocale is now the default, no need to enforce it anymore
Delete some duplicate code that was harmless because
exactly the same code is at the end of the nfscl_checksattr()
function that is called just before it. As such, this code
had already been executed and didn't do anything.

MFC after:	1 week
Merge remote-tracking branch 'freebsd/master' into hardened/current/master