New v3 failures on AIX. mt_alloc?

[Benjamin Kosnik]

>	The testcases appear to be failing in mt_allocator::allocate(),
>specifically 
>
>              _S_bin[bin].first[0] =
>                static_cast<block_record*>(::operator new(_S_options._M_chunk_s
>ize));

Thanks I'm looking into this.

best,
benjamin