commit-graph: add missing forward declaration

jonathantanmy · gitster · commit e5c5ca27292d · 2018-07-17T15:47:48.000-07:00
Signed-off-by: Jonathan Tan &lt;jonathantanmy@google.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/commit-graph.h b/commit-graph.h
@@ -5,6 +5,8 @@
 #include "repository.h"
 #include "string-list.h"
 
+struct commit;
+
 char *get_commit_graph_filename(const char *obj_dir);
 
 /*
