run_mta.sh on MAC OS ulimit: open files: cannot modify limit: Invalid argument

The run_mta.sh script trys to set the soft ulimit to 100000 which causes an issue on a MAC OS.

An error is reported
/run_mta.sh: line 25: ulimit: open files: cannot modify limit: Invalid argument

The workaround is to edit the run_mta.sh script
Change line 7 from
WE_NEED=100000
to
WE_NEED=10000