sed error message reports byte position instead of char position when program contains UTF-8

[Camion SPAM]

In case of error in a sed program, sed error message reports byte position 
instead of char position when program contains UTF-8.

$ sed 's/qwerty///'
sed: -e expression #1, char 11: unknown option to `s'
$ sed 's/qwérty///' 
sed: -e expression #1, char 12: unknown option to `s'
$ sed --version
GNU sed version 4.2.1

(For if it is not obvious, there is an "e acute" instead of an "e" in the 
second expression)