[gfortran,patch] Fix intrinsics used as actual arguments

[FX Coudert]

> If it is a trivial backport (15 minutes and regression test),
> then I would think that it is worth.  If it requires any effort
> then I think the port is not worth it.

It turned out to be more than that, as I originally had to make a  
succession of commits that are not backporting trivially (and also,  
the big diff to intrinsic.c is hard to backport automatically). So, I  
didn't backport it.

FX