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.

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.