Strictly speaking it is not legal to forward declare an enum.

bin/varnishd/cache/cache.h

@@ -192,11 +192,6 @@ enum httpwhence {
  * Ban info event types
  */
 
-enum baninfo {
-	BI_NEW,
-	BI_DROP
-};
-
 /* NB: remember to update http_Copy() if you add fields */
 struct http {
 	unsigned		magic;

bin/varnishd/common/common.h

@@ -40,6 +40,16 @@
 #include "vqueue.h"
 #include "vsb.h"
 
+/*
+ * Enums cannot be forward declared (any more...) so put it here
+ * to make everybody see it.
+ */
+
+enum baninfo {
+	BI_NEW,
+	BI_DROP
+};
+
 struct cli;
 
 /**********************************************************************

bin/varnishd/storage/storage.h

@@ -38,7 +38,6 @@ struct busyobj;
 struct objcore;
 struct worker;
 struct lru;
-enum baninfo;
 
 typedef void storage_init_f(struct stevedore *, int ac, char * const *av);
 typedef void storage_open_f(const struct stevedore *);