Fix weak handling with GCC 3.4+

[Geoff Keating]

Richard Henderson <rth@twiddle.net> writes:

> On Fri, Jan 03, 2003 at 02:34:50PM -0800, Ulrich Drepper wrote:
> > __thread int foo = 0;
> > extern __typeof (foo) foo __attribute ((weak));
> > 
> > 
> > __typeof() apparently does not include the __thread information.  I'd
> > call it a gcc bug.
> 
> Why do you say that?  __thread is a storage class specifier, not a
> type specifier.  It would be just as incorrect if __typeof somehow
> copied "static" or "extern".
> 
> IMO this idiom is simply incorrect wrt __thread.
> 
> It would work if you used
> 
>   extern __thread __typeof(foo) foo __attribute((weak));
> 
> or just 
> 
>   #pragma weak foo

Another underspecified GCC extension!

I would expect that in

__thread int foo = 0;
extern __typeof (foo) foo;

the second declaration would have no effect, just as in

static int foo = 0;
extern __typeof (foo) foo;

because 'extern' is not a storage class specifier.

-- 
- Geoffrey Keating <geoffk@geoffk.org>