Compatibility: 5.0+
Expects: AX    ad83H
                                                                  
Returns: BL    flag: 00H = default keyboard
ffH = alternate keyboard
                                                                  
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.

The return value, in BL, identifies which keyboard layout is
currently active. BL=00H indicates that the Ctrl+Alt+F1 (default)
is active and BL=ffH indicates that the Ctrl+Alt+F2 (secondary)
layout is active.

- -

INT 2fH ad83H: Query KEYB.COM Country Flag