Make EVP_MD_CTX size functions return size_t.

The EVP_MD versions do, so the types should bubble up.

BUG=22

Change-Id: Ibccbc9ff35bbfd3d164fc28bcdd53ed97c0ab338
Reviewed-on: https://boringssl-review.googlesource.com/7687
Reviewed-by: Steven Valdez <svaldez@google.com>
Reviewed-by: David Benjamin <davidben@google.com>

crypto/digest/digest.c

@@ -231,11 +231,11 @@ const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx) {
   return ctx->digest;
 }
 
-unsigned EVP_MD_CTX_size(const EVP_MD_CTX *ctx) {
+size_t EVP_MD_CTX_size(const EVP_MD_CTX *ctx) {
   return EVP_MD_size(EVP_MD_CTX_md(ctx));
 }
 
-unsigned EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx) {
+size_t EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx) {
   return EVP_MD_block_size(EVP_MD_CTX_md(ctx));
 }
 

include/openssl/digest.h

@@ -218,11 +218,11 @@ OPENSSL_EXPORT const EVP_MD *EVP_MD_CTX_md(const EVP_MD_CTX *ctx);
 
 /* EVP_MD_CTX_size returns the digest size of |ctx|, in bytes. It
  * will crash if a digest hasn't been set on |ctx|. */
-OPENSSL_EXPORT unsigned EVP_MD_CTX_size(const EVP_MD_CTX *ctx);
+OPENSSL_EXPORT size_t EVP_MD_CTX_size(const EVP_MD_CTX *ctx);
 
 /* EVP_MD_CTX_block_size returns the block size of the digest function used by
  * |ctx|, in bytes. It will crash if a digest hasn't been set on |ctx|. */
-OPENSSL_EXPORT unsigned EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx);
+OPENSSL_EXPORT size_t EVP_MD_CTX_block_size(const EVP_MD_CTX *ctx);
 
 /* EVP_MD_CTX_type returns a NID describing the digest function used by |ctx|.
  * (For example, |NID_sha256|.) It will crash if a digest hasn't been set on