[PATCH 3/4] msvcp90: Define basic_string for runtime_error when not msvcirt.

[Daniel Lehman]

>> Ah, I don't need it.  the existing runtime_error functions are individually #ifndef _MSVCIRT like the rest that are exported by msvcirt, and I admittedly hadn't noticed that it wasn't exported by msvcirt.  Could the whole runtime_error just be #ifndef _MSVCIRT?
> Yes, it can be put inside ifndef block.

the rest of the series ok?  they don't depend on it

thanks
daniel