MFC r234772:

MFC r234772:
  Import stdbuf(1) and the shared library it relies on.
  This tool changes the default buffering behaviour of standard
  stdio streams.

  It only works on dynamic binaries.  To make it work for static
  ones it would require cluttering stdio because there no single
  entry point.

  PR:		166660
  Reviewed by:	current@, jhb
  Approved by:	kib (mentor)
  MFC after:	1 week

MFC r234773:
  Fix small documentation mistakes.

  Submitted by:	brueffer
  Approved by:	kib (mentor)

MFC r234779:
  Use standard getopt(3) error message.

  Submitted by:	jilles
  Approved by:	kib (mentor)

git-svn-id: svn://svn.freebsd.org/base/stable/9@235139 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f