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.