[tuples] C++ify gimple.h

[Diego Novillo]

On 10/12/07, Aldy Hernandez <aldyh@redhat.com> wrote:

>         * gimple.h (_ALLOC_GSI): New.
>         Use it throughout when allocating a new gimple_stmt_iterator.

Actually, it's much better if we have a static inline gsi_alloc()
routine that returns a new iterator.

It will be helpful for a future cleanup I have in mind.  We are
allocating these iterators in GC memory, which may be pretty wasteful.
 If we have a single allocation point, we can do things like a pool of
GSIs in the near future.