swift234

Allow enum elements with string raw values to default to the name of the element.

Just like enums with integer raw values can get autoincrementing case values,
enums with string raw values get the name of the element. The name is /not/
prefixed with the enum type because the purpose is presumably to interoperate
with a string-based system, which may require either writing or printing the
raw value as a string.

If an enum's raw type is both integer literal convertible and string literal
convertible, the integer side wins. That is, elements without raw values
will get auto-incremented integer values, rather than string values, and will
produce an error if an auto-incremented value cannot be generated.

rdar://problem/15819953

Swift SVN r29542