Replace deprecated GnuTLS functions gnutls_*_set_priority with gnutls_priority_set_direct.

The functions gnutls_*_set_priority we used were marked deprecated since
latest GnuTLS version 2.12. However the replacement function
gnutls_priority_set_direct is available since 2.2, which is even lower
than our version requirement 2.4 in configure. The patch just replace
the deprecate function to fix the compile warning.
Signed-off-by: Vic Lee <llyzs@163.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

libvncclient/tls.c

@@ -31,10 +31,8 @@
 
 #ifdef LIBVNCSERVER_WITH_CLIENT_TLS
 
-static const int rfbCertTypePriority[] = { GNUTLS_CRT_X509, 0 };
-static const int rfbProtoPriority[]= { GNUTLS_TLS1_1, GNUTLS_TLS1_0, GNUTLS_SSL3, 0 };
-static const int rfbKXPriority[] = {GNUTLS_KX_DHE_DSS, GNUTLS_KX_RSA, GNUTLS_KX_DHE_RSA, GNUTLS_KX_SRP, 0};
-static const int rfbKXAnon[] = {GNUTLS_KX_ANON_DH, 0};
+static const char *rfbTLSPriority = "NORMAL:+DHE-DSS:+RSA:+DHE-RSA:+SRP";
+static const char *rfbAnonTLSPriority= "NORMAL:+ANON-DH";
 
 #define DH_BITS 1024
 static gnutls_dh_params_t rfbDHParams;
@@ -133,6 +131,7 @@ static rfbBool
 InitializeTLSSession(rfbClient* client, rfbBool anonTLS)
 {
   int ret;
+  const char *p;
 
   if (client->tlsSession) return TRUE;
 
@@ -142,12 +141,10 @@ InitializeTLSSession(rfbClient* client, rfbBool anonTLS)
     return FALSE;
   }
 
-  if ((ret = gnutls_set_default_priority(client->tlsSession)) < 0 ||
-      (ret = gnutls_kx_set_priority(client->tlsSession, anonTLS ? rfbKXAnon : rfbKXPriority)) < 0 ||
-      (ret = gnutls_certificate_type_set_priority(client->tlsSession, rfbCertTypePriority)) < 0 ||
-      (ret = gnutls_protocol_set_priority(client->tlsSession, rfbProtoPriority)) < 0)
+  if ((ret = gnutls_priority_set_direct(client->tlsSession,
+    anonTLS ? rfbAnonTLSPriority : rfbTLSPriority, &p)) < 0)
   {
-    rfbClientLog("Warning: Failed to set TLS priority: %s.\n", gnutls_strerror(ret));
+    rfbClientLog("Warning: Failed to set TLS priority: %s (%s).\n", gnutls_strerror(ret), p);
   }
 
   gnutls_transport_set_ptr(client->tlsSession, (gnutls_transport_ptr_t)client);