[patch/rfc] Add host's floatformat

[Andrew Cagney]

>>This patch adds the host's floatformat (when known) to floatformat.[hc]. 
> 
> 
> Since we *are* the host, don't we *always* know what the host't float
> format is?  I mean, we can just cast to float.  But still, we should
> be able to auto-detect which floatformat is used at runtime, rather
> than guess in configure (and miss lots of host processors).
> 
> We should be able to have a pre-compiled table of float constants and
> their hex representations, and just scan the table for bit equality to
> see which entries match.
> 
> It might be a bit more complex to code the first time around, but it
> will be a lot less hackish in the long run (and maintenance-free :)

The patch, which is effectively lifed from GDB's code base has been 
working well.  However, I'll change those variables to functions so that 
the possability you describe can be easily implemented.

Andrew