Change the date format of gnumeric

Another one of those #@!*! things that you expect to be in the preferences of gnumeric or in gnome control center somewhere, but no. In a new install of Fedora, gnumeric suddenly started showing my dates in the ridiculous US format. Of course I don't want to format individual cells in gnumeric.

It turns out this fixes it:

• if you're using tcsh, add this to your .cshrc:
  setenv LC_TIME "en_GB.UTF_8"
• if you're using bash:
  export LC_TIME="en_GB.UTF_8"

For en_GB.UTF_8 pick your preferred locale.