[v3] default linux allocator

[Mark Mitchell]

Benjamin Kosnik wrote:

>>You need to justify why you want to move this to the 3.4 branch, unless 
>>it is fixing a regression.
>>    
>>
>
>Of course. 
>
>Do you think this is something that the linux vendors should just agree
>on, to include a --enable-libstdcxx-allocator=mt along with
>--enable-__cxa_atexit for toolchains?
>
>Personally, I would prefer to set the defaults in the configury.
>  
>
If you think that all GNU/Linux users should have this new behavior, 
then it should be the default in the configury.  But, on the 3.4 branch, 
we should convince ourselves that (a) it's not an ABI change, and (b) 
it's a major win.

What's the purpose of this change?  If 3.4.1 was good enough for a user, 
why does that user, in the context of getting a bugfix release, need 
this change?  And will it be backwards compatible with existing code?  
Could I recompile just some of the files in my app with 3.4.2 and relink 
with existing 3.4.1 object files, or do I have to recompile everything?

Thanks,

-- 
Mark Mitchell
CodeSourcery, LLC
(916) 791-8304
mark@codesourcery.com