[gfortran,patch] Fix code generated for NINT

[Paul Thomas]

FX,
>
> I've bootstrapped and regtested on x86_64-linux, but I'd be glad if 
> someone with a platform without full C99 support, and especiall 
> lround, could test it.  I once had access to a sparc-solaris2.9, which 
> fulfilled these criteria, but not more.
>
Does Cygwin comply? I am just about to launch a regtest.  I am only 
asking because the consequences of the NINT bug are particularly dire. :-)

Paul