<iostream> badly broken?!?

[Paolo Carlini]

Hi,

I just built Rev 174696 and if I run the following snippet in the bash 
shell of an x86_64-linux machine, today I don't get any meaningful 
output, in particular I don't get 'ok', instead '|+000|', which I have 
no idea what it means:

#include <iostream>

int main()
{
   std::cout << "ok\n";
}

Can anybody else see this crazy breakage? May be a few days old, AFAICS. 
4_6-branch is perfectly fine.

To be clear, nothing important changed in the <iostream> code of the 
library itself over the next weeks.

Paolo.