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

MFC devd-related changes

r270004
Convert devd's client socket to type SOCK_SEQPACKET.

This change consists of two merges from projects/zfsd/head along with the
addition of an ATF test case for the new functionality.

sbin/devd/tests/Makefile
sbin/devd/tests/client_test.c
Add ATF test cases for reading events from both devd socket types.

r266519:
sbin/devd/devd.8
sbin/devd/devd.cc
Create a new socket, of type SOCK_SEQPACKET, for communicating with
clients. SOCK_SEQPACKET sockets preserve record boundaries,
simplying code in the client. The old SOCK_STREAM socket is retained
for backwards-compatibility with existing clients.

r269993:
sbin/devd/devd.8
Fix grammar bug.

r270019 (from bz)
Remove bogus ; at the end of the if condition in order to unbreak gcc builds
after r270004.

MFC after: 4 days
X-MFX with: r270004

MFC r263774:

Revert r263694, and apply a better fix to squelch unnecessary warnings
from clang about possible keywords being treated as identifiers for the
remainder of the translation unit (a.k.a. -Wkeyword-compat), when using
libstdc++ in combination with -Wsystem-headers. This will not only fix
devd, but any C++ program using libstdc++.

MFC r263694:

Apply a temporary band-aid for building devd with clang 3.4, libstdc++
and -Wsystem-headers enabled (which is the default for any non-zero
WARNS level, crazily enough!). This is primarily meant to be MFC'd as
soon as possible.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Bump WARNS where possible.

Checked by: make universe
Approved by: ed (co-mentor)

Reduce the WARNS level across the board due to a warning that occurs
on at least arm and sparc64. i386/pc98, ia64 and amd64 are all OK.

Use pidfile(3).

OK'ed by: imp

Make devd WARNS=4 clean and bump WARNS accordingly. This will insure
that future variable shadowing bugs don't compile.

Reviewed by: imp
Compiled on: alpha i386 sparc64

NOSHARED -> NO_SHARED

At imp's request, force devd to be statically compiled. This avoids the
need for libstdc++ in /lib, and the generated binary is actually smaller
statically linked than dynamically + sizeof(libstdc++). Additionally,
devd doesn't use get*by*() which is one of the main motivations for
dynamically linking your root partition anyway.

This can't obviously be cleaner than system headers.

MFp4 (imp_freebsd branch): snapshot of devd work:
o improve parsing and lexing
o create data structures based on the parsed file now.
o Still need to rewrite main loop and add regex (still uses hard coded
devd-generic)
o minor man page updates.

# There should be one more commit before rc2

Approved by: re (blanket)

Install devd.conf(5).

devd. A daemon that hooks into the kernel's /dev/devctl to produce
arbitrary commands when devices come and go in the device tree (which is
different than the /dev directory).

This is an initial version. Much of the planned power isn't here.
Instead of doing the full matching, we always run /etc/devd-generic.
/etc/devd.generic will go away at some point, I think.

I'm committing it in this early state so I can start getting feedback
from early adapters.

Approved by: re