Libstdc++-v3 vs darwin vs weak support

[Paolo Carlini]

Benjamin Kosnik wrote:

>>I'd like to know from the maintainers (or other knowledgeable people) 
>>which is the current situation, whether those explicit instantiations 
>>are still needed. I'm asking because I mean to move from v7 to mainline 
>>a bunch of similar testcases...
>>    
>>
>I think you should kill these bits, for a couple of reasons. One, I
>don't know if they are necessary when using mt_alloc circa 20050315. I'm
>thinking that they are not, just due to design changes. Two, mt_alloc is
>not the default allocator for darwin, or for other platforms that are
>hostile to weak symbols.
>  
>
Ah! Many thanks Benjamin for the clarifications: f.i., I was completely 
missing
that on "non-weak" platforms in fact we don't use mt_alloc at all 
(confirmed by
David Edelsohn). That, alone, pretty much closes the issue!

Therefore, my plan would be first removing the gunk from the existing 
testcases
in mainline and wait a bit just in case something breaks...

Paolo.