[foreign] RFR: Port clang-ffi source code to new API

[Maurizio Cimadamore]

> You use the same name as struct and typedef, thus in your test case you have UndefinedStruct as the fact it’s a typedef.
>
> See the test case in the webrev, for struct.h
>
>     8 typedef struct UndefineStructForPointer *UndefinedStructPointer;
>     9
>    10 struct Opaque* allocate_opaque_struct();
>
> jextract no longer generate UndefineStructForPoitner nor Opaque as annotations.
Right - I see now what you did - you added test cases for these change 
in behavior; while I mistakenly assumed you changed an existing test 
(e.g. I missed the changes in struct.h).

Looks good
Maurizio
>
> Cheers,
> Henry
>
>