patch 8.0.0607: after :bwipe + :new bufref might still be valid
Problem: When creating a bufref, then using :bwipe and :new it might get
the same memory and bufref_valid() returns true.
Solution: Add br_fnum to check the buffer number didn't change.
diff --git a/src/globals.h b/src/globals.h
index 1d67b0d..7bc5471 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -385,7 +385,7 @@
/* When deleting the current buffer, another one must be loaded. If we know
* which one is preferred, au_new_curbuf is set to it */
-EXTERN bufref_T au_new_curbuf INIT(= {NULL COMMA 0});
+EXTERN bufref_T au_new_curbuf INIT(= {NULL COMMA 0 COMMA 0});
/* When deleting a buffer/window and autocmd_busy is TRUE, do not free the
* buffer/window. but link it in the list starting with