[Bug-wget] TLS1.3 via GnuTLS patch

[Loganaden Velvindron]

Hi guys, I've tested this patch with:

./src/wget --secure-protocol=TLSv1_3 https://tls13.crypto.mozilla.org/
--2018-07-16 19:45:31--  https://tls13.crypto.mozilla.org/
Resolving tls13.crypto.mozilla.org... 52.32.149.186
Connecting to tls13.crypto.mozilla.org|52.32.149.186|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 3456 (3.4K) [text/html]
Saving index.html.

index.html.3         100%[===================>]   3.38K  --.-KB/s    in 0s      

2018-07-16 19:45:32 (63.2 MB/index.html. saved [3456/3456]
3s) 

diff --git a/src/gnutls.c b/src/gnutls.c
index 07844c52..6ceec705 100644
--- a/src/gnutls.c
+++ b/src/gnutls.c
@@ -564,6 +564,9 @@ set_prio_default (gnutls_session_t session)
     case secure_protocol_tlsv1_2:
       err = gnutls_priority_set_direct (session, 
"NORMAL:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1", NULL);
       break;
+    case secure_protocol_tlsv1_3:
+      err = gnutls_priority_set_direct (session, 
"NORMAL:-VERS-SSL3.0:-VERS-TLS1.0:-VERS-TLS1.1:-VERS-TLS1.2:+VERS-TLS1.3", 
NULL);
+      break;
 
     case secure_protocol_pfs:
       err = gnutls_priority_set_direct (session, "PFS:-VERS-SSL3.0", NULL);
@@ -610,6 +613,11 @@ set_prio_default (gnutls_session_t session)
       err = gnutls_protocol_set_priority (session, allowed_protocols);
       break;
 
+    case secure_protocol_tlsv1_3:
+      allowed_protocols[0] = GNUTLS_TLS1_3;
+      err = gnutls_protocol_set_priority (session, allowed_protocols);
+      break;
+
     default:
       logprintf (LOG_NOTQUIET, _("GnuTLS: unimplemented 'secure-protocol' 
option value %d\n"), opt.secure_protocol);
       logprintf (LOG_NOTQUIET, _("Please report this issue to 
bug-wget@gnu.org\n"));