test old code

src/core/opamSystem.ml

@@ -217,7 +217,7 @@ let remove_file file =
   )
 
 let string_of_channel ic =
-  let n = Stdlib.in_channel_length ic in
+  let n = 4096 in
   let b = Buffer.create n in
   let rec iter ic b =
     match Buffer.add_channel b ic n with