Fix compile error on windows when not building with GnuTLS
diff --git a/win/rfb_win32/SecurityPage.cxx b/win/rfb_win32/SecurityPage.cxx
index f0c21af..e540702 100644
--- a/win/rfb_win32/SecurityPage.cxx
+++ b/win/rfb_win32/SecurityPage.cxx
@@ -120,7 +120,9 @@
 
 bool
 SecurityPage::onOk() {
+#ifdef HAVE_GNUTLS
   bool x509_loaded = false;
+#endif
   bool vnc_loaded = false;
   list<U32> secTypes;