wantcache -- Return or update Expint cache desirabilty status
 
  SYNOPSIS:
        wantcache(stat)
    b = wantcache
 
  PARAMETERS:
    stat - New cache disirability status.  OPTIONAL.
           Used as a boolean flag stating whether or not caching is
           wanted.
 
           Possible values are
             - FALSE, 0, 'false', 'off', 'no', 'n' -- caching unwanted
             - anything else                       -- caching wanted
 
           Case is insignificant in string values.
 
  RETURNS:
    b   - Boolean value indicating whether or not caching is wanted.
          OPTIONAL.