[fortran,patch] Allow some IEEE functions in constant and specification expressions

[FX]

> This looks fine to me. OK for trunk.

Thanks for review. Committed as revision 226723.


> I am not sure how you communicate the IEEE support to the front, since
> you need to be able to support cross-compilation. I identification of
> the hardware architecture sufficient?

Indeed, it is tricky to achieve, because identification of the target triplet is not sufficient. We need to test some functions/macros too.

FX