[PATCH, fortran] Interoperability with C int128_t types

[Sa Liu]

> I'm not a native speaker, but i think this should either read
> "the standards that support" or "the standard that supports".
> 
> To me, the former sounds more accurate iff we or several standards
> together (in the future).
> The same applies to the other occurances in this proposed patch (which i
> stopped reading here).
> 

Thanks for the remark. I think "the standard that supports" is more 
appropriate since (currently) only one standard can be specified by the 
forth parameter of the macro.
I will correct it in source file.

Sa