Consistently apply this rule: the guard name is obtained from the
filename by stripping the leading "lib", converting '/' and '.' to
'_' and uppercasing the resulting name. Guard names in the root
directory have to be prefixed by "FFMPEG_".
Originally committed as revision 15120 to svn://svn.ffmpeg.org/ffmpeg/trunk
Not only the repeated byte is calculated as (count ^ xor) + add
but also the raw encoding lenth byte is calculated as that too
patch by Xiaohui Sun sunxiaohui dsp ac cn
Originally committed as revision 8602 to svn://svn.ffmpeg.org/ffmpeg/trunk
