Function:   MaxHandles()

               In the Summer '87 version of Expand, there was a SetHandles()
               function. But that does not work anymore in Clipper 5.0, so
               using the SET CLIPPER=, or burn in variables will have to be
               used now again. MaxHandles() function will return a
               number indicating how many files could be open at one time,
               making it possible for you to exit gracefully instead of some
               obscure message when there's no more handles left.

   Syntax:     MaxHandles() --> nMax

   Arguments:  None.

   Returns:    The max # of open files.

   Usage:      * - Check if Ok to open 70 files..
               if MaxHandles() < 70
                    ? 'Please adapt CONFIG.SYS and/or SET CLIPPER'
                    quit
               end
               * - This will allow you to open 30 databases
               * - with One index file each (for example)