Convert to use libxo.

Obtained from:	Phil Shafer <phil@juniper.net>
Sponsored by:	Juniper Networks, Inc.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274125 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Document that wc(1) supports libxo(3).


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274126 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
In alloc_pread() and kern_pread(), print errors only when DEBUG is
defined. An error is not fatal and is supposed to be handled by the
caller.

Obtained from:	Juniper Networks, Inc.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274127 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f