format-patch: improve head calculation for cover-letter

diff --git a/resolve-undo.h b/resolve-undo.h
index 845876911db978c6262dacd9aa122ce9d55bf234..7a30206aad1fdee74f7e7b6e5967f9f8d9048dbf 100644 (file)
--- a/resolve-undo.h
+++ b/resolve-undo.h
@@ -12,5 +12,6 @@ extern struct string_list *resolve_undo_read(const char *, unsigned long);
 extern void resolve_undo_clear_index(struct index_state *);
 extern int unmerge_index_entry_at(struct index_state *, int);
 extern void unmerge_index(struct index_state *, const char **);
+extern void unmerge_marked_index(struct index_state *);
 
 #endif