[libstdc++-v3] Remove std::construct and std::destroy

[Jason Merrill]

>>>>> "Benjamin" == Benjamin Kosnik <bkoz@redhat.com> writes:

>> So, in summary, nonstandard names can be removed from std, and should
>> remain available through the backward headers.  Behaviour should be
>> according to the standard, but alternate (documented SGI) behaviour
>> should be available through a compile time switch.

> Please, no comple time switch for changing to broken signatures. That's an 
> invitation to disaster. Let's just do it right, and if necessary document 
> the difference.

Agreed.

Jason