[libstdc++] intptr_t usage

[Paolo Carlini]

Jakub Jelinek wrote:

>IMHO it is far better to just use int __attribute__((__mode__ (__pointer__)))
>in libstdc++ headers and don't suggest that it is necessarily the same type
>as intptr_t or uintptr_t.
>  
>
Or just use __conditional_type which covers all the cases we actually 
care about.

Thanks,
Paolo.