patch 8.1.1298: invalid argument test fails without X clipboard

Problem:    Invalid argument test fails without X clipboard.
Solution:   Test -display only with the +xterm_clipboard feature.
diff --git a/src/version.c b/src/version.c
index da0d1df..90f9e87 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1298,
+/**/
     1297,
 /**/
     1296,