Chapter 15 of the RG covers Email. Section 15.3.4 has this to say about m4:
"By default, the m4 macro processor is installed with Sendmail and is part of
the sendmail-cf package."
This is wrong. m4 is actually supplied by its own package, m4.
[root@station2 tora]# rpm -qf /usr/bin/m4
Thanks for the catch!
I will be posting an errata about this issue this week.
I appreciate you taking the time to post this bug.
I have posted an errata and corrected the HTML on the Web site.
Thanks so much for taking the time to call this to my attention!