INT 21 - DoubleDOS - SET/RESET KEYBOARD CONTROL FLAGS                           
	AH = E8h
	AL = program for which to set flags (00h this program, 01h other)
	DX = keyboard control flags (see #02088)
Return: DX = previous flags
Notes:	disabling Ctrl-PrtSc will allow the program to intercept the keystroke;
	  disabling any of the other keystrokes disables them completely
	identical to AH=F8h
SeeAlso: AH=E1h"DoubleDOS",AH=E2h"DoubleDOS",AH=E3h"DoubleDOS"
SeeAlso: AH=F8h"DoubleDOS"


Bitfields for DoubleDOS keyboard control flags:
Bit(s)	Description	(Table 02088)
 0	menu
 1	exchange
 2	entire keyboard enable/disable
 3	Ctrl-C
 4	Ctrl-PrtSc
 5	Alt/Erase
 6	Ctrl-Break
 7	Ctrl-NumLock
 8	shift-PrtSc
 9-13	undefined
 14	cancel key (clear keyboard buffer)
 15	suspend key
Note:	setting a enables the corresponding key or operatin, clearing a
	  disables it