suspect check in ringbuffer.c

[noasic]

RingBuffer_write() checks for RingBuffer_available_space() but reports RingBuffer_available_data(). Also, the request/available order does not seem to be correct:

    check(length <= RingBuffer_available_space(buffer),
            "Not enough space: %d request, %d available",
            RingBuffer_available_data(buffer), length);