TLS compression only allocates working buffer once
diff --git a/include/polarssl/ssl.h b/include/polarssl/ssl.h
index cf18ea7..3e3ace3 100644
--- a/include/polarssl/ssl.h
+++ b/include/polarssl/ssl.h
@@ -667,6 +667,9 @@
size_t out_msglen; /*!< record header: message length */
size_t out_left; /*!< amount of data not yet written */
+#if defined(POLARSSL_ZLIB_SUPPORT)
+ unsigned char *compress_buf; /*!< zlib data buffer */
+#endif
#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
unsigned char mfl_code; /*!< MaxFragmentLength chosen by us */
#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */