patch 8.1.1297: invalid argument test fails without GTK

Problem:    Invalid argument test fails without GTK.
Solution:   Test -display and --display separately.
diff --git a/src/version.c b/src/version.c
index 8e6b404..da0d1df 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1297,
+/**/
     1296,
 /**/
     1295,