Compile error when MBEDTLS_SSL_MAX_FRAGMENT_LENGTH is enabled.

[lhuang04]

When I turned on MBEDTLS_SSL_MAX_FRAGMENT_LENGTH in tls13-prototype branch.

diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 9a8cd63ad..7b73f2f1c 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -1690,7 +1690,7 @@
  *
  * Comment this macro to disable support for the max_fragment_length extension
  */
-//#define MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
+#define MBEDTLS_SSL_MAX_FRAGMENT_LENGTH

I got the following compiler error.

/home/lhuang04/upstream/library/ssl_tls13_client.c: In function ‘ssl_client_hello_write_partial’:
/home/lhuang04/upstream/library/ssl_tls13_client.c:1757:5: error: passing argument 3 of ‘ssl_write_max_fragment_length_ext’ makes integer from pointer without a cast [-Werror]
     ssl_write_max_fragment_length_ext( ssl, buf, end, &cur_ext_len );
     ^
/home/lhuang04/upstream/library/ssl_tls13_client.c:551:12: note: expected ‘size_t’ but argument is of type ‘unsigned char *’
 static int ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
            ^
cc1: all warnings being treated as errors
make[2]: *** [library/CMakeFiles/mbedtls.dir/ssl_tls13_client.c.o] Error 1
make[2]: *** Waiting for unfinished jobs....
[ 34%] Built target cert_req
/home/lhuang04/upstream/library/ssl_tls.c: In function ‘mbedtls_ssl_get_input_max_frag_len’:
/home/lhuang04/upstream/library/ssl_tls.c:5708:23: error: ‘MBEDTLS_SSL_SERVER_HELLO_DONE’ undeclared (first use in this function)
         ssl->state >= MBEDTLS_SSL_SERVER_HELLO_DONE )
                       ^
/home/lhuang04/upstream/library/ssl_tls.c:5708:23: note: each undeclared identifier is reported only once for each function it appears in
/home/lhuang04/upstream/library/ssl_tls13_server.c: In function ‘ssl_write_max_fragment_length_ext’:
/home/lhuang04/upstream/library/ssl_tls13_server.c:3080:9: error: ‘return’ with a value, in function returning void [-Werror]
         return( 0 );
         ^
/home/lhuang04/upstream/library/ssl_tls13_server.c:3085:9: error: ‘return’ with a value, in function returning void [-Werror]
         return( 0 );
         ^
/home/lhuang04/upstream/library/ssl_tls13_server.c: In function ‘ssl_encrypted_extensions_write’:
/home/lhuang04/upstream/library/ssl_tls13_server.c:3394:5: error: passing argument 3 of ‘ssl_write_max_fragment_length_ext’ makes pointer from integer without a cast [-Werror]
     ret = ssl_write_max_fragment_length_ext( ssl, p, end - p, &n );
     ^
/home/lhuang04/upstream/library/ssl_tls13_server.c:3070:13: note: expected ‘size_t *’ but argument is of type ‘long int’
 static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
             ^
make[2]: *** [library/CMakeFiles/mbedtls.dir/ssl_tls.c.o] Error 1
[ 34%] Built target cert_write
/home/lhuang04/upstream/library/ssl_tls13_server.c:3394:5: error: too many arguments to function ‘ssl_write_max_fragment_length_ext’
     ret = ssl_write_max_fragment_length_ext( ssl, p, end - p, &n );
     ^
/home/lhuang04/upstream/library/ssl_tls13_server.c:3070:13: note: declared here
 static void ssl_write_max_fragment_length_ext( mbedtls_ssl_context *ssl,
             ^
/home/lhuang04/upstream/library/ssl_tls13_server.c:3394:9: error: void value not ignored as it ought to be
     ret = ssl_write_max_fragment_length_ext( ssl, p, end - p, &n );
         ^
cc1: all warnings being treated as errors
make[2]: *** [library/CMakeFiles/mbedtls.dir/ssl_tls13_server.c.o] Error 1
make[1]: *** [library/CMakeFiles/mbedtls.dir/all] Error 2
make: *** [all] Error 2