static inline
    SilcBuffer silc_buffer_senlarge(SilcStack stack, SilcBuffer sb,
                                    SilcUInt32 size);

    Enlarges the buffer by the amount of `size' if it doesn't have that
    must space in the data area and in the tail area.  Moves the tail
    area automatically after enlarging so that the current data area
    is at least the size of `size'.  If there is more space than `size'
    in the data area this does not do anything.  If there is enough
    space in the tail area this merely moves the tail area to reveal
    the extra space.  Returns FALSE on error.

    This routine use SilcStack are memory source.  If `stack' is NULL
    reverts back to normal allocating routine.