Rename ff_mpeg1_decode_block_intra to mpeg1_decode_block_intra and
make it static. Add ff_mpeg1_decode_block_intra as plain extern
function calling mpeg1_decode_block_intra.
Originally committed as revision 18859 to svn://svn.ffmpeg.org/ffmpeg/trunk
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
