Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r226422, r227241, r228063, r228697, r228698, r228701, r234310, r234850,
r250226, r250926.

This brings m4 up to date with the version in head and fixes the eval
command when called with a 2nd and 3rd argument. The only differences
remaining are related to the updated flex and byacc in head.

PR: bin/166994

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Remove the advertising clause from UCB copyrighted files in usr.bin. This
is in accordance with the information provided at
ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change

Also add $FreeBSD$ to a few files to keep svn happy.

Discussed with: imp, rwatson

m4 script to test the functionality of math operators in eval().

Submitted by: K S Braunsdorf <sed@ksb.npcguild.org>

This commit was generated by cvs2svn to compensate for changes in r16748,
which included commits to RCS files with non-trunk default branches.

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