Bitfields for APPEND state:
Bit(s)	Description	)
 0	set if APPEND enabled
 1-11	reserved
 12	(DOS 5.0) set if APPEND applies directory search even if a drive has
	  been specified
 13	set if /PATH flag active
 14	set if /E flag active (environment var APPEND exists)
 15	set if /X flag active