Fix typo.

--HG--
branch : HEAD

TODO

diff --git a/TODO b/TODO
index 095d83c..e49d184 100644
--- a/TODO
+++ b/TODO
@@ -3,7 +3,7 @@
 + [portability] use _setmode(_fileno(fp), _O_BINARY); where present
 + [bug] missing -Wl,-R in pkg-config file
 - [doc] document that no empty archives will be created
-- [bug] zip_close: on empty archive, don't try to delete non-existant file
+- [bug] zip_close: on empty archive, don't try to delete non-existent file
 - [bug] zip_merge: zip_close too early for source archives
 - [feature] torrentzip support
   . two flag members in struct zip (has, should)