[fortran patch] Don't use TREE_LISTs for storing arguments to intrinsic functions

[FX Coudert]

> Would you mind if I committed it, then?  I'd prefer to get this  
> into the tree sooner, rather than having to worry about bit-rot  
> (especially since FX is working on a patch in the same area).

I'm already on it! Currently regtesting, will commit later tonight.

FX