This makes it much more flexible, at the expense of making it a little
more fragile. I can think of a number of scenarios where we'll have
paths that have variables in multiple spots, and I don't want to do
sprintf() magic every time I need to access an object at one of those
paths.
This also makes UtilGetDelim() and UtilGetLine() thread safe in that it
isn't setting a global errno. Of course, errno should be thread safe
already, but this makes it much less ambiguous.
