Make generation of nslexer.c more robust.

Ensure that lex errors fail the build instead of being silently ignored
due to the piped call.  Also postpone the update of the nslexer.c file
until we are sure we have generated it properly.

These changes fix some very obscure build failures I encountered while
building FreeBSD within a chroot that did not have devfs mounted. The
specific errors looked like:

.../libc.so.7: undefined reference to `_nsyyerror'
.../libc.so.7: undefined reference to `_nsyyin'
.../libc.so.7: undefined reference to `_nsyylex'
.../libc.so.7: undefined reference to `_nsyylineno'
.../libc.so.7: undefined reference to `_nsyytext'

and were caused due to a mangled nslexer.c being linked into libc.
Don't report non-native block-size pools under zpool status -x

zpool status -x is used to identify pools that are exhibiting
errors or are otherwise unavailable, therefore non-native
block-size pools shouldn't be reported.

Also update man page to clarify other additional conditions
which won't cause a pool to be displayed under zpool status -x.

Sponsored by:	Multiplay
Eliminate dead code.  There is no direct map.  This code was cut-and-pasted
from amd64.
On my Lenovo laptop, the firmware maps the EFI framebuffer with MTRRs set
to uncacheable. This leads to execrable console performance. Once PMAP is
up, remap the framebuffer as write-combining. This reduces boot time on my
laptop by 60% when booting with EFI.

MFC after:	2 weeks
Bump mdoc date after r268621.

X-MFC-With:	r268621
Minor (mostly cosmetic) cleanups

Several whitespace fixes
convert *rootDir from external to static.

Obtained from:	NetBSD, OpenBSD (partial)
MFC after:	3 days
fsck_msdosfs: be a bit more permissive

The free space value in the FSInfo block is merely unitialized when it is
0xffffffff. This fixes a bug found in NetBSD.

It must be noted that we never supported all the checks that NetBSD does
as some of them would cause failures with a freshly created FAT32
from MS-Windows.

While here, bring some space fixes.

Obtained from:	NetBSD (rev. 1.22)
MFC after:	3 days
msdosfs: Assorted fixes from other BSDs.

When truncating cluster chains fix the length of the cluster head.
http://marc.info/?t=140304310700005&r=1&w=2

Avoid infinite loops in cluster chain linked lists.
http://marc.info/?l=openbsd-tech&m=140275150804337&w=2

Avoid off-by-one on FAT12 filesystems.
http://marc.info/?l=openbsd-tech&m=140234174104724&w=2

Obtained from:	NetBSD (from OpenBSD)
MFC after:	1 week
Fix the Zedboard/Zynq ethernet driver to handle media speed changes so
that it can connect to switches at speeds other than 1gb.

This requires changing the reference clock speed.  Since we still don't
have a general clock API that lets a SoC-independant driver manipulate its
own clocks, this change includes a weak reference to a routine named
cgem_set_ref_clk().  The default implementation is a no-op; SoC-specific
code can provide an implementation that actually changes the speed.

Submitted by:	Thomas Skibo <ThomasSkibo@sbcglobal.net>
Manage struct sigacts refcnt with atomics instead of a mutex.

MFC after:	1 week
newfs_msdosfs: Respect FSFIXFAT

Fix some whitespace issues while here.

Obtained from:	NetBSD (rev. 1.9)
MFC after:	3 days
Plug p_pptr null test in do_execve. It is always true.
fortune(8): Search fortune files installed by ports/packages as well as
those supplied by the base system.

PR:		191800
Submitted by:	Andy Kosela
MFC after:	1 week
Add a call to synthesize a C/H/S value for block emulations
that require it (ahci). The algorithm used is from the VHD
specification.
Use the blockif CHS routine to create fake CHS values,
and then populate them in the identity page.

This fixes a divide-by-zero error at probe time with NetBSD.

MFC after:	1 week.
Allow multi-byte reads in the private CHELSIO_T4_GET_I2C ioctl.  The
firmware allows up to 48B to be read this way but the driver limits
itself to 8B at a time to remain compatible with old cxgbetool
binaries.

MFC after:	1 week
Fix an issue with service(8) where utilities such as screen(1) and tmux(1)
would behave differently when utilizing rc-script was invoked manually vs.
service(8). The issue being that these utilities require the TERM environ
variable to be set and service(8) was not passing it down.

Reported by:	Michael Dexter <editor@callfortesting.org>
PR:		bin/191869
Reviewed by:	allanjude
MFC after:	3 days
X-MFC-to:	stable/10, stable/9
libc/gen: small updates to code originating at OpenBSD

arc4random.c
- CVS rev. 1.22
Change arc4random_uniform() to calculate ``2**32 % upper_bound'' as
``-upper_bound % upper_bound''. Simplifies the code and makes it the
same on both ILP32 and LP64 architectures, and also slightly faster on
LP64 architectures by using a 32-bit remainder instead of a 64-bit
remainder.
- CVS rev. 1.23
Spacing

readpassphrase.c
-CVS rev. v 1.24
most obvious unsigned char casts for ctype

Obtained from:	OpenBSD
MFC after:	5 days
Document that listen(2) can fail with EDESTADDRREQ.
libc/stdlib: Minor cleanups to code originating in NetBSD

Mostly ANSIfication and typos.

Obtained from:	NetBSD
MFC after:	5 days