patch 7.4.2324
Problem:    Crash when editing a new buffer and BufUnload autocommand wipes
            out the new buffer. (Norio Takagi)
Solution:   Don't allow wiping out this buffer. (partly by Hirohito Higashi)
            Move old style test13 into test_autocmd. Avoid ml_get error when
            editing a file.
diff --git a/src/structs.h b/src/structs.h
index ebeefd0..a44bcec 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1845,8 +1845,8 @@
 
     int		b_flags;	/* various BF_ flags */
 #ifdef FEAT_AUTOCMD
-    int		b_closing;	/* buffer is being closed, don't let
-				   autocommands close it too. */
+    int		b_locked;	/* Buffer is being closed or referenced, don't
+				   let autocommands wipe it out. */
 #endif
 
     /*