[gfortran,patch] Add ISO_FORTRAN_ENV module

[FX Coudert]

> One other item.  Do you need to use uppercase names for
> the symbols (e.g., "IOSTAT_END" instead of "iostat_end")?
> I know that gfortran translates lowercase to upper as it
> parses a file.  I tried tracing through the code to see
> when/if uppercase is needed.

No, I think gfortran translates uppercase to lowercase when parsing  
the file, hence my choice for lowercase symbol names. We also use  
lowercase names, e.g., for intrinsic procedures.

I'll commit the patch soon with Tobias' and Brooks' changes.

Thanks everyone,
FX