Update example in readme

README.md

@@ -13,12 +13,12 @@ Inspired by [Ruby's FFI](https://github.com/ffi/ffi)
 defmodule MyLib do
   use FFI.Library
 
-  ffi_lib "c"
+  ffi_lib "libstdc++.so.6"
 
   attach_function :puts, [:string], :int
 end
 
-MyLib.puts(["Hello world"])
+MyLib.puts(["Hello World from C stdlib"])
 ```
 
 ## Installation