MFC r261774 by feld:

	Add caveat to zpool manpage indicating that we do not automatically activate
	hot spares. This should be MFC'd to all STABLE branches.

	Upon the availability of zfsd, the zpool manpage on relevant branches should
	be updated to remove this caveat and document hot spare's reliance on zfsd.

Requested by:	feld
MFC r262125:

In sys/dev/usb/controller/uss820dci.c, similar to r261977, fix a warning
about uss820dci_odevd being unused, by adding it to the part that
handles getting descriptors.

Reported by:	loos
Reviewed by:	hselasky
MFC r262310:

Move the part in bsd.own.mk that sets -Wno-c++11-extensions for clang to
bsd.sys.mk, where it really belongs.  This also causes the flag to get
added when clang is *not* the default system compiler, but is still
used, e.g. by setting WITH_CLANG_IS_CC manually.
MFC r262467: sh: Add -h option to SYNOPSIS

Reviewed by:	jilles
[automated] Merge in upstream-github/stable/9