[GCC-XML]Various bits not mentioned in XML output

[Brad King]

> - Typedefs are output as <Typedef> elements, but never seem to be
> referenced. A typedef function argument will be output as an <Argument>
> with the typedef's underlying type.
>
> - Declarations (specifically, function prototypes) are not output as XML
> unless there's no corresponding definition, in which case they're
> written with an extern="1" attribute. Would it be possible to output
> declarations even when a definition *is* found, with a prototype="1" or
> somesuch to distinguish the two?

You are correct, these are due to limitations of the GCC parser because it
doesn't need to know this information.  I haven't looked at the new GCC
front-end, but it may support this information.

> - File-scope static (as opposed to class-member static) is not marked.
> (I'm fairly sure I've seen a "linkage_kind" or somesuch in the GCC
> source, but it may be new; they have a completely rewritten C++ frontend
> now.)

This one could probably be fixed, but I don't have time to look into it
now.  Reading through cp-tree.h in the 3.0.4 source tree might give you a
clue on how to add it, though.

-Brad