Log Message:
Update ast-ksh to 20021221.

Changes from 20020922 (other than bug fixes) are:

	* The code to display compound objects was rewritten to make it easier
	  for runtime extensions to reuse this code.
	* A change was made to allow runtime builtins to be notified when a
	  signal is received so that cleanup can be performed.
	* User applications can now trap the ALRM signal.  Previously, the ALRM
	  signal was used internally and could not be used by applications.