Add a TODO-note about crypt.c
diff --git a/TODO b/TODO
index 225034a..5edb8a3 100644
--- a/TODO
+++ b/TODO
@@ -18,5 +18,8 @@
 What also needs to be implemented is the capability of the tools to
 handle data with NUL-bytes in it.
 
+The return values of mdcheckline() in crypt.c need to be fixed (0 -> success,
+1 -> error).
+
 [0] http://landley.net/toybox/roadmap.html
 [1] http://git.suckless.org/ubase/