3.2 PATCH: Fix _IEEE_FP etc. definitions on alpha

[Rainer Orth]

Neil Booth writes:

> Oops, sorry about that.

No problem: I just need to run bootstraps more often :-)

> > The following trivial patch fixes this.
> > 
> > C-only bootstrap in progress.  Ok for mainline if it passes?
> 
> I think your patch qualifies as obvious in this case.

Probably: the bootstrap finished, removing the regression, so I went ahead
and installed the patch as obvious.

	Rainer