external: Do not confuse new gcc

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

src/external/bcrypt_pbkdf.c

@@ -87,7 +87,7 @@ bcrypt_hash(uint8_t *sha2pass, uint8_t *sha2salt, uint8_t *out)
 		cdata[i] = Blowfish_stream2word(ciphertext, sizeof(ciphertext),
 		    &j);
 	for (i = 0; i < 64; i++)
-		ssh_blf_enc(&state, cdata, sizeof(cdata) / sizeof(uint64_t));
+		ssh_blf_enc(&state, cdata, BCRYPT_BLOCKS/2);
 
 	/* copy out */
 	for (i = 0; i < BCRYPT_BLOCKS; i++) {