swift234

[PrintAsObjC] Print 'struct Foo' or 'enum Foo' instead of 'Foo' when necessary.

To do this, we keep track of decls with superfluous typedefs (rather than
just the typedefs), and check for that. Tag decls without typedefs are
printed with the tag.

<rdar://problem/17569385>

Swift SVN r20221