[c++0x] std::thread fixes

[Benjamin Kosnik]

Can we break this patch down into a couple patches, and move a bit more
incrementally?

> As discussed recently, the names in std::thread don't follow the
> libstdc++ coding style.

Whoops, I missed this. Please don't change

-  class __thread_data_base;
+  class _Thread_data_base;
 
There is no need to do this.

Your member function changes to _M_ are fine.

> There's a memory leak in the case where a new thread can't be started,
> because of the shared_ptr cycle created in _M_this_ptr.

Next patch.
 
> The std::thread move constructor and assignment operator definitions
> are missing.

Add these in with the renames.

>  _Thread_data_base doesn't need a mutex, and doesn't need to derive
> from enable_shared_from_this.

Next patch.


I'd like to separate out the renames/adding missing bits from the other
changes.

thanks,
benjamin