Fix iovec-related tests

Author: kovdan01

test/buffer_c.cpp

@@ -102,7 +102,7 @@ TEST(buffer, vrefbuffer_c)
                     MSGPACK_VREFBUFFER_REF_SIZE + 1,
                     ref_size, chunk_size + 1};
     size_t iovcnt;
-    const iovec *iov;
+    const msgpack_iovec *iov;
     size_t len = 0, i;
     char *buf;
 

test/msgpack_c.cpp

@@ -1616,7 +1616,7 @@ TEST(MSGPACKC, object_bin_print_buffer_overflow) {
 #define GEN_TEST_VREFBUFFER_PREPARE(...)                       \
     msgpack_vrefbuffer vbuf;                                   \
     msgpack_packer pk;                                         \
-    const iovec *iov;                                          \
+    const msgpack_iovec *iov;                                  \
     size_t iovcnt, len = 0, i;                                 \
     char buf[1024];                                            \
     msgpack_vrefbuffer_init(&vbuf, 0, 0);                      \