JuliaLang/julia — pull request #6042 by tkelman (2014-03-04 07:08:59+00:00)
Title: More descriptive error for environment variable not found

When `ERROR: key not found: "foo"` happens deep in some internal function, it's not always obvious that it's referring to an environment variable. Bikeshedding on the error message welcome (or if this needs to be done differently), but I think this is a special enough case that it should get a specific message.