-unsigned long av_adler32_update(unsigned long adler, const uint8_t *buf,
- unsigned int len) av_pure;
+AVAdler av_adler32_update(AVAdler adler, const uint8_t *buf,
+#if FF_API_CRYPTO_SIZE_T
+ unsigned int len) av_pure;
+#else
+ size_t len) av_pure;
+#endif