Fix various errors

Signed-off-by: Xiaokang Qian <xiaokang.qian@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 086f980..2d805ad 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1180,7 +1180,9 @@
     mbedtls_time_t MBEDTLS_PRIVATE(start);       /*!< starting time      */
 #endif
     int MBEDTLS_PRIVATE(ciphersuite);            /*!< chosen ciphersuite */
+#if defined(MBEDTLS_SSL_SESSION_TICKETS)
     int MBEDTLS_PRIVATE(res_ciphersuite);        /*!< resumption ciphersuite */
+#endif
     size_t MBEDTLS_PRIVATE(id_len);              /*!< session id length  */
     unsigned char MBEDTLS_PRIVATE(id)[32];       /*!< session identifier */
     unsigned char MBEDTLS_PRIVATE(master)[48];   /*!< the master secret  */