blake: add compat macros

blake2b.h

@@ -25,6 +25,8 @@ typedef struct __blake2b_state
 } blake2b_state;
 
 #define BLAKE2B_CTX blake2b_state
+#define BLAKE2B_BLOCK_LENGTH   BLAKE2B_BLOCKBYTES
+#define BLAKE2B_DIGEST_LENGTH  BLAKE2B_OUTBYTES
 
 int blake2b_Init(blake2b_state *S, size_t outlen);
 int blake2b_InitKey(blake2b_state *S, size_t outlen, const void *key, size_t keylen);

blake2s.h

@@ -25,6 +25,8 @@ typedef struct __blake2s_state
 } blake2s_state;
 
 #define BLAKE2S_CTX blake2s_state
+#define BLAKE2S_BLOCK_LENGTH   BLAKE2S_BLOCKBYTES
+#define BLAKE2S_DIGEST_LENGTH  BLAKE2S_OUTBYTES
 
 int blake2s_Init(blake2s_state *S, size_t outlen);
 int blake2s_InitKey(blake2s_state *S, size_t outlen, const void *key, size_t keylen);