XQuartz, utf-8 and filenames

This is a question in the continuation of this one: UTF8 filenames and shell utilities : the nightmare of utf-8 and filenames is…. How to avoid this confusion with most notably the ls command on filnames created in the following way: $ echo $LANG en_US.UTF-8 $ mkdir test $ cd test $ touch á $ touch a´ $ The first file is created by typing alt ⌥+E, A, the second one by typing A, alt ⌥+shift ⇧+E Within an xterm window I get: $ ls -al total 0 drwxr-xr-x 2 hal admin 136 Nov 11 15:52 . drwxr-x--- 7 hal admin 4386 Nov 11 14:25 .. -rw-r--r-- 1 hal admin 0 Nov 11 15:52 a´ -rw-r--r-- 1 hal admin 0 Nov 11 15:48 a´ $ Which is wrong. Within a Terminal window I get: $ ls -al total 0 drwxr-xr-x 2 hal admin 136 Nov 11 15:52 . drwxr-x--- 7 hal admin 4386 Nov 11 14:25 .. -rw-r--r-- 1 hal admin 0 Nov 11 15:52 a´ -rw-r--r-- 1 hal admin 0 Nov 11 15:48 á $ Which is right. The result is the same whichever shell I use: bash or zsh. What xterm or XQuartz setting will avoid these 2 filenames to falsely look the same? This problem doesn't exist on Mavericks (MacOS X 10.9).