Globally rename the header inclusion guard names.

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

libavcodec/acelp_vectors.h

@@ -20,8 +20,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#ifndef FFMPEG_ACELP_VECTORS_H
-#define FFMPEG_ACELP_VECTORS_H
+#ifndef AVCODEC_ACELP_VECTORS_H
+#define AVCODEC_ACELP_VECTORS_H
 
 #include <stdint.h>
 
@@ -150,4 +150,4 @@ void ff_acelp_weighted_vector_sum(
         int shift,
         int length);
 
-#endif /* FFMPEG_ACELP_VECTORS_H */
+#endif /* AVCODEC_ACELP_VECTORS_H */