Missed one.

src/core/census/placeholders.c

@@ -81,6 +81,10 @@ census_view *census_view_create(uint32_t metric_id, const census_tag_set *tags,
   abort();
 }
 
+const census_tag_set *census_view_tags(const census_view *view) {
+  (void)view;
+}
+
 void census_view_delete(census_view *view) {
   (void)view;
   abort();