Eh... not quite. Setting argv[0] in the process should work on most POSIX systems. That change is an additional thing it does for Linux, and notes the limit for that.

This is on a Mac.:

$ perl -e '$0="my really awesome process name"; sleep 60;' &
[1] 73413
$ ps
  PID TTY           TIME CMD
70164 ttys002    0:00.05 /opt/local/bin/bash
  677 ttys004    0:05.06 /opt/local/bin/bash
73413 ttys004    0:00.03 my really awesome process name
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