egs-parallel-clean does not work on macOS

[mchamberland]

egs-parallel-clean does not work on macOS:

~/dev/EGSnrc/egs_home/egs_brachy (myegs*) » egs-parallel-clean -n ex_single_source                              marc@Moridin
egs-parallel-clean
current directory: /Users/marc/dev/EGSnrc/egs_home/egs_brachy/

CLEANING ex_single_source ...
    ! TESTING only: with the -f (--force) option, egs-parallel-clean WOULD:
    ! create ex_single_source.egsparallel-log (merged egs-parallel log messages)
    ! create ex_single_source.egsparallel-out (merged parallel jobs output streams)
find: illegal option -- m
usage: find [-H | -L | -P] [-EXdsx] [-f path] path ... [expression]
       find [-H | -L | -P] [-EXdsx] -f path [path ...] [expression]

If my web searching is correct, it appears the macOS find is based on BSD whereas the egs-parallel-clean assumes gnu-based find.