Make renegotiation a compile-time option

include/polarssl/config.h

@@ -821,6 +821,19 @@
  */
 //#define POLARSSL_SSL_HW_RECORD_ACCEL
 
+/**
+ * \def POLARSSL_SSL_RENEGOTIATION
+ *
+ * Enable support for TLS renegotiation.
+ *
+ * The two main uses of renegotiation are (1) refresh keys on long-lived
+ * connections and (2) client authentication after the initial handshake.
+ * If you don't need renegotiation, it's probably better to disable it, since
+ * it has been associated with security issues in the past and is easy to
+ * misuse/misunderstand.
+ */
+#define POLARSSL_SSL_RENEGOTIATION
+
 /**
  * \def POLARSSL_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO
  *