Made support for the max_fragment_length extension configurable
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index ac72832..772b2c9 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -276,6 +276,7 @@
 }
 #endif
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
 static void ssl_write_max_fragment_length_ext( ssl_context *ssl,
                                                unsigned char *buf,
                                                size_t *olen )
@@ -299,6 +300,7 @@
 
     *olen = 5;
 }
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
 static void ssl_write_truncated_hmac_ext( ssl_context *ssl,
                                           unsigned char *buf, size_t *olen )
@@ -546,8 +548,10 @@
     ext_len += olen;
 #endif
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
     ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
+#endif
 
     ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
@@ -621,6 +625,7 @@
     return( 0 );
 }
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
 static int ssl_parse_max_fragment_length_ext( ssl_context *ssl,
                                               const unsigned char *buf,
                                               size_t len )
@@ -638,6 +643,7 @@
 
     return( 0 );
 }
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
 static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
                                          const unsigned char *buf,
@@ -891,6 +897,7 @@
 
             break;
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
         case TLS_EXT_MAX_FRAGMENT_LENGTH:
             SSL_DEBUG_MSG( 3, ( "found max_fragment_length extension" ) );
 
@@ -901,6 +908,7 @@
             }
 
             break;
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
         case TLS_EXT_TRUNCATED_HMAC:
             SSL_DEBUG_MSG( 3, ( "found truncated_hmac extension" ) );
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 7de1577..ff0e9d1 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -564,6 +564,7 @@
 }
 #endif /* POLARSSL_ECP_C */
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
 static int ssl_parse_max_fragment_length_ext( ssl_context *ssl,
                                               const unsigned char *buf,
                                               size_t len )
@@ -578,6 +579,7 @@
 
     return( 0 );
 }
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
 static int ssl_parse_truncated_hmac_ext( ssl_context *ssl,
                                          const unsigned char *buf,
@@ -1174,6 +1176,7 @@
             break;
 #endif /* POLARSSL_ECP_C */
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
         case TLS_EXT_MAX_FRAGMENT_LENGTH:
             SSL_DEBUG_MSG( 3, ( "found max fragment length extension" ) );
 
@@ -1181,6 +1184,7 @@
             if( ret != 0 )
                 return( ret );
             break;
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
         case TLS_EXT_TRUNCATED_HMAC:
             SSL_DEBUG_MSG( 3, ( "found truncated hmac extension" ) );
@@ -1386,6 +1390,7 @@
     *olen = 5 + ssl->verify_data_len * 2;
 }
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
 static void ssl_write_max_fragment_length_ext( ssl_context *ssl,
                                                unsigned char *buf,
                                                size_t *olen )
@@ -1410,6 +1415,7 @@
 
     *olen = 5;
 }
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
 static int ssl_write_server_hello( ssl_context *ssl )
 {
@@ -1551,8 +1557,10 @@
     ssl_write_renegotiation_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
     ssl_write_max_fragment_length_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
+#endif
 
     ssl_write_truncated_hmac_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index bb605b9..1281bc8 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -59,6 +59,7 @@
 #define strcasecmp _stricmp
 #endif
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
 /*
  * Convert max_fragment_length codes to length.
  * RFC 6066 says:
@@ -75,6 +76,7 @@
     2048,                   /* SSL_MAX_FRAG_LEN_2048 */
     4096,                   /* SSL_MAX_FRAG_LEN_4096 */
 };
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
 static int ssl_session_copy( ssl_session *dst, const ssl_session *src )
 {
@@ -3238,6 +3240,7 @@
     ssl->min_minor_ver = minor;
 }
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
 int ssl_set_max_frag_len( ssl_context *ssl, unsigned char mfl_code )
 {
     if( mfl_code >= sizeof( mfl_code_to_length ) ||
@@ -3250,6 +3253,7 @@
 
     return( 0 );
 }
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
 int ssl_set_truncated_hmac( ssl_context *ssl, int truncate )
 {
@@ -3555,7 +3559,7 @@
 {
     int ret;
     size_t n;
-    unsigned int max_len;
+    unsigned int max_len = SSL_MAX_CONTENT_LEN;
 
     SSL_DEBUG_MSG( 2, ( "=> write" ) );
 
@@ -3568,19 +3572,21 @@
         }
     }
 
+#if defined(POLARSSL_SSL_MAX_FRAGMENT_LENGTH)
     /*
      * Assume mfl_code is correct since it was checked when set
      */
     max_len = mfl_code_to_length[ssl->mfl_code];
 
     /*
-     * Check if a smaller max length was negociated
+     * Check if a smaller max length was negotiated
      */
     if( ssl->session_out != NULL &&
         mfl_code_to_length[ssl->session_out->mfl_code] < max_len )
     {
         max_len = mfl_code_to_length[ssl->session_out->mfl_code];
     }
+#endif /* POLARSSL_SSL_MAX_FRAGMENT_LENGTH */
 
     n = ( len < max_len) ? len : max_len;