Add search function to libtar

 Function entryExists() can be called in order
 to check if an entry exists inside an archive.

Change-Id: Id3d13d20dfb74a1779dbd8ba6f0ab08c3ca46319
diff --git a/libtar/libtar.h b/libtar/libtar.h
index f2f423b..1d6c1df 100644
--- a/libtar/libtar.h
+++ b/libtar/libtar.h
@@ -291,6 +291,8 @@
 /* add a whole tree of files */
 int tar_append_tree(TAR *t, char *realdir, char *savedir);
 
+/* find an entry */
+int tar_find(TAR *t, char *searchstr);
 
 #ifdef __cplusplus
 }