updated for version 7.3.1303
Problem: Undo is synced whenever CTRL-R = is called, breaking some plugins.
Solution: Only break undo when calling setline() or append().
diff --git a/src/globals.h b/src/globals.h
index 1e966cf..feb1dd4 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -916,6 +916,10 @@
EXTERN int allow_keys INIT(= FALSE); /* allow key codes when no_mapping
* is set */
EXTERN int no_u_sync INIT(= 0); /* Don't call u_sync() */
+#ifdef FEAT_EVAL
+EXTERN int u_sync_once INIT(= 0); /* Call u_sync() once when evaluating
+ an expression. */
+#endif
EXTERN int restart_edit INIT(= 0); /* call edit when next cmd finished */
EXTERN int arrow_used; /* Normally FALSE, set to TRUE after