When a string enumeration has the empty string as one of its available
values, the generated code for many languages is invalid because the
empty string can not be used as an identifier. As with numbers and
symbols, provide a mapping to an English name which can be used as a
replacement. In this case, "empty" for the empty string/empty value.
Signed-off-by: Kevin Locke <kevin@kevinlocke.name>
