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

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

Add the -p flag to force unknown control sequences to be passed
through unchanged.

Reviewed by: silence on -audit
Obtained from: NetBSD
MFC after: 3 weeks

This commit was generated by cvs2svn to compensate for changes in r1590,
which included commits to RCS files with non-trunk default branches.

BSD 4.4 Lite Usr.bin Sources