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/rangecoder.h

@@ -24,8 +24,8 @@
  * Range coder.
  */
 
-#ifndef FFMPEG_RANGECODER_H
-#define FFMPEG_RANGECODER_H
+#ifndef AVCODEC_RANGECODER_H
+#define AVCODEC_RANGECODER_H
 
 #include <stdint.h>
 #include <assert.h>
@@ -138,4 +138,4 @@ static inline int get_rac(RangeCoder *c, uint8_t * const state){
 #endif
 }
 
-#endif /* FFMPEG_RANGECODER_H */
+#endif /* AVCODEC_RANGECODER_H */