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.
CR: https://reviews.freebsd.org/rS266519
MFC after: 5 days
Sponsored by: Spectra Logic