[Patch] Nathan's improvements to basic_string

[Loren James Rittle]

> Everything considered we believe with Loren (more expert
> than me of MT topics) that [Nathan's string impl] patch
> should go in as soon as possible, but nevertheless will
> wait some additional 24 hours, just in case...

I can confirm that I tested the exact logical patch that you posted on
{i386,alpha}-unknown-freebsd4 even though I updated it myself.

My only concern (in terms of committing it ASAP to mainline) might be
that this is at least a reverse incompatibility.  It may be (i.e. I
think it is but haven't personally tested it) forward compatible.

Regards,
Loren