Restructuring i386_extract_return_value

[Jim Kingdon]

>   There is a switch `-mno-fp-ret-in-387' to force GCC to return
>   floating-point values in the ordinary CPU registers.  I don't think
>   this can be determined from the debugging information.  Is it worth
>   adding a i386 target specific option to enable people to debug
>   this code?

IMHO, no.  People who use ABI-warping flags do so at their own risk.

As for the rest of the patch, it looked right to me.  Not that I tried
to track down every last issue that you mention.