Compatibility: 5.0+
Expects: AX    ad82H
BL    flag: 00H = default keyboard
ffH = alternate keyboard
                                                                  
Returns: CF    Carry Flag is set if there is an error
                                                                  
Info: When KEYB.COM is active and the KEYBOARD.SYS has been installed,
you can toggle between one keyboard layout an another via
Ctrl+Alt+F1 and Ctrl+Alt+F2.  Clearing the country flag (BL=00H)
is equivalent to the former and setting the country flag (BL=ffH)
is equivalent to the latter.

- -

INT 2fH ad82H: Set KEYB.COM Country Flag