Re: [rfa/arm] Fix some structs.exp failures

[Richard Earnshaw <rearnsha@arm.com>]

>    check_typedef is completely 
>    undocumented -- no mention in the internals documentation, and not even a 
>    comment in gdbtypes.[ch].
> 
> There is one comment about check_typedef()/CHECK_TYPEDEF() in
> gdbtypes.h.  Anyway, Daniels fix is OK.  Before you look at a type the
> way arm_use_struct_convention does, you should have called
> check_typedef(), otherwise you'll look at the typedef itself, and not
> its underlying type.
> 

I guess if you call a comment on an (apparently) unrelated macro 400 lines 
earlier in the file documentation then I was wrong.  However, that still 
begs a load of questions:

What are the input parameters?

What is returned?

What is it safe to pass?

Can it be called more than once?

Does it operate recursively?

Does it change the input parameter, or is a new object created?

Some of these may be obvious from analysing the source, but that shouldn't 
really be necessary.

R.