[libstdc++ patch] Fix ambiguity in calls to bind

[Paolo Carlini]

Hi Doug,

>A recent change to mainline GCC exposed an ambiguity in function template 
>partial ordering for tr1::bind. The compiler is right, so here's the 
>"obvious" fix.
>
>Tested i686-pc-linux-gnu on mainline; no regressions. Okay for mainline?
>This will also be needed on the 4.0 branch. Assuming all tests pass there, 
>okay for 4.0 branch?
>  
>
this is certainly OK with me, more generally, as far as I'm concerned
you are fully responsible for your own tr1 code. Just allow a minimum of
time for all the maintainers to have a look.

Paolo.