patch 8.1.2122: cannot build without terminal feature

Problem:    Cannot build without terminal feature.
Solution:   Add #ifdef.
diff --git a/src/version.c b/src/version.c
index f4d0275..e207a37 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2122,
+/**/
     2121,
 /**/
     2120,