const correctness: make HMAC_size() take a const *

CLA: none; trivial
Signed-off-by: NKurt Roeckx <kurt@roeckx.be>
Reviewed-by: NRich Salz <rsalz@openssl.org>

GH: #1070

crypto/hmac/hmac.c

@@ -164,7 +164,7 @@ int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)
     return 0;
 }
 
-size_t HMAC_size(HMAC_CTX *ctx)
+size_t HMAC_size(const HMAC_CTX *ctx)
 {
     return EVP_MD_size((ctx)->md);
 }

include/openssl/hmac.h

@@ -67,7 +67,7 @@
 extern "C" {
 #endif
 
-size_t HMAC_size(HMAC_CTX *e);
+size_t HMAC_size(const HMAC_CTX *e);
 HMAC_CTX *HMAC_CTX_new(void);
 int HMAC_CTX_reset(HMAC_CTX *ctx);
 void HMAC_CTX_free(HMAC_CTX *ctx);