merged all the latest changes from 2.4 to trunk

3rdparty/include/ffmpeg_/libavutil/random_seed.h

@@ -22,10 +22,22 @@
 #define AVUTIL_RANDOM_SEED_H
 
 #include <stdint.h>
+/**
+ * @addtogroup lavu_crypto
+ * @{
+ */
 
 /**
  * Get a seed to use in conjunction with random functions.
+ * This function tries to provide a good seed at a best effort bases.
+ * Its possible to call this function multiple times if more bits are needed.
+ * It can be quite slow, which is why it should only be used as seed for a faster
+ * PRNG. The quality of the seed depends on the platform.
  */
 uint32_t av_get_random_seed(void);
 
+/**
+ * @}
+ */
+
 #endif /* AVUTIL_RANDOM_SEED_H */