Fix weak handling with GCC 3.4+

[Geoff Keating]

> Date: Fri, 3 Jan 2003 15:03:59 -0800
> From: Richard Henderson <rth@twiddle.net>

> On Fri, Jan 03, 2003 at 02:53:53PM -0800, Geoff Keating wrote:
> > Another underspecified GCC extension!
> 
> No it isn't.

Perhaps 'incorrectly specified'?

The specification in extend.texi says 

> An object whose identifier is declared with the storage-class
> specifier @w{@code{__thread}} has @dfn{thread storage duration}.

So, consider this program fragment:

> > __thread int foo = 0;        // line 1
> > extern __typeof (foo) foo;   // line 2

line 1 is a declaration (and also a definition, but never mind that)
of 'foo', and it includes the storage-class specifier __thread.  Thus,
'foo' has thread storage duration.  The result would be the same if
this was written

extern int foo;
__thread int foo = 0;

or

extern __thread int foo;
int foo = 0;

...
> Please re-read the documentation I wrote for __thread.
> It contains rationale for why all declarations of foo
> must specify __thread.

Is the extend.texi documentation what you were thinking of?  I can't
see anywhere it says that all declarations must specify __thread.

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