enum: Allow specifying the name used when none of the flags are set

src/libcharon/sa/child_sa.c

@@ -42,6 +42,7 @@ ENUM(child_sa_state_names, CHILD_CREATED, CHILD_DESTROYING,
 );
 
 ENUM_FLAGS(child_sa_outbound_state_names, CHILD_OUTBOUND_REGISTERED, CHILD_OUTBOUND_POLICIES,
+	"NONE",
 	"REGISTERED",
 	"SA",
 	"POLICIES",