Avoid C99 inside C++ code

This disrupts building at least with Visual Studio.

Signed-off-by: Alexey Rusakov <ktirf@users.sf.net>

include/olm/cipher.h

@@ -123,9 +123,9 @@ extern const struct _olm_cipher_ops _olm_cipher_aes_sha_256_ops;
  *   struct _olm_cipher *cipher = OLM_CIPHER_BASE(&MY_CIPHER);
  */
 #define OLM_CIPHER_INIT_AES_SHA_256(KDF_INFO) {     \
-    .base_cipher = { &_olm_cipher_aes_sha_256_ops },\
-    .kdf_info = (uint8_t *)(KDF_INFO),              \
-    .kdf_info_length = sizeof(KDF_INFO) - 1         \
+    /*.base_cipher = */{ &_olm_cipher_aes_sha_256_ops },\
+    /*.kdf_info = */(uint8_t *)(KDF_INFO),              \
+    /*.kdf_info_length = */sizeof(KDF_INFO) - 1         \
 }
 #define OLM_CIPHER_BASE(CIPHER) \
     (&((CIPHER)->base_cipher))

src/account.cpp

@@ -167,7 +167,7 @@ std::size_t olm::Account::get_one_time_keys_json_length(
         }
         is_empty = false;
         length += 2; /* {" */
-        length += olm::encode_base64_length(olm::pickle_length(key.id));
+        length += olm::encode_base64_length(_olm_pickle_uint32_length(key.id));
         length += 3; /* ":" */
         length += olm::encode_base64_length(sizeof(key.key.public_key));
         length += 1; /* " */
@@ -198,8 +198,8 @@ std::size_t olm::Account::get_one_time_keys_json(
         }
         *(pos++) = sep;
         *(pos++) = '\"';
-        std::uint8_t key_id[olm::pickle_length(key.id)];
-        olm::pickle(key_id, key.id);
+        std::uint8_t key_id[_olm_pickle_uint32_length(key.id)];
+        _olm_pickle_uint32(key_id, key.id);
         pos = olm::encode_base64(key_id, sizeof(key_id), pos);
         *(pos++) = '\"'; *(pos++) = ':'; *(pos++) = '\"';
         pos = olm::encode_base64(