Locale codeset UTF-8 vs. utf8

[Michael Schwendt <mschwendt gmail com>]

Default GNOME user in Fedora 9:

  $ env|grep LANG
  LANG=en_US.utf8
  GDM_LANG=en_US.utf8

Logging in as superuser:

  $ su -
  # env|grep LANG
  LANG=en_US.UTF-8

Switching back to normal user:

  # su - user
  $ env|grep LANG
  LANG=en_US.UTF-8

The difference in the spelling of the codeset breaks Sylpheed (#450063)
which only looks for codeset "UTF-8". Now where again is it defined
that both are valid spellings for the codeset?

$ locale -a|grep utf8|wc -l
230
$ locale -a|grep UTF-8|wc -l
2