roffcmds.icn: Program to list roff commands and macros

   This progam processes standard input and writes a tabulation of
nroff/troff commands and defined strings to standard output.

Limitations:

   This program only recognizes commands that appear at the beginning of
lines and does not attempt to unravel conditional constructions.
Similarly, defined strings buried in disguised form in definitions are
not recognized.

Reference:

   Nroff/Troff User's Manual, Joseph F. Ossana, Bell Laboratories,
Murray Hill, New Jersey. October 11, 1976.