Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

- Correct mispellings of word and

Submitted by: Christoph Mallon <christoph.mallon@gmx.de> (via private mail)

Restore Python 2.6+ compatibility

SVN r245536 ported this to Python 3. The major change was the use of the
print function. Unfortunately this is incompatible with Python 2, which
is still the default version in the ports tree.

Use a __future__ import to make this compatible with Python 2.6 and later.

Convert to Python 3

Approved by: cperciva

Add a new tool which attempts to check for kernel configuration options that
are missing from NOTES files.