NAME
    KMayGetChar - return a character if present, but don't wait
                  (defaults to the serial port at 9600 baud)

SYNOPSIS
    flagChar = KMayGetChar()
    D0

FUNCTION
    return either a -1, saying that there is no character present, or
    whatever character was waiting.  KMayGetChar is the assembly
    interface,  _KMayGetChar is the C interface.