Preserve the relation btw. file-name-coding-system & the 'file-name c-s alias.
lisp/ChangeLog addition:
2009-01-13 Aidan Kehoe <kehoea@parhasard.net>
* mule/mule-cmds.el (set-language-environment-coding-systems):
Fix a cosmetic bug; the relationship between
file-name-coding-system and the file-name coding system alias
established in coding.el wasn't being maintained. See Katsumi
Yamaoka's comment in http://mid.gmane.org/b4m4p03bt43.fsf@jpl.org .