SMFLSTEN - Sample ENF listener

This module controls the following two sample listener user exit routines:

SMFLSTAL - Gains control for all qualifier values
SMFLST00 - Only gains control if qualifier equals ENF37Q00

For each listener user exit routine, this module issues the ENFREQ LISTEN request, waits for the associated processing to complete and then issues the ENFREQ DELETE request.

A program that listens for ENF events should perform the following:

Initialize Module
- Perform Entry Linkage
  - Save input registers
  - MODESET to key 0, Supervisor State
- Get Working Storage
Set Module Recovery
When the module ends abnormally, its ESTAE routine attempts a RETRY to ensure that ENFREQ DELETE deletes all of the listen requests.
Set up for ENF Listen Requests
- Ensure that the listener user exits are in common storage
- Issue an ENFREQ LISTEN request (with or without a qualifier)