Recognizing/translating cpu names

[Mikael Vidstedt]

All,

On linux/SPARC the platform string returned from config.guess is 
"sparc64-unknown-linux-gnu", but the build system doesn't currently 
recognize "sparc64" as a valid cpu name. I'd like some feedback on how 
to address this. I can see two ways:

1. Add it to the list of recognized cpu names and map it to the "normal" 
sparc values, something like:

http://cr.openjdk.java.net/~mikael/webrevs/top-sparc64/webrev.00/webrev/

2. Massage/translate the string in config.guess to return something 
better (e.g. sparcv9-unknown-linux-gnu)

I notice that we do the latter type of translation for some 
platforms/strings, but it's not clear to me what the pros and cons are 
of the respective approaches. Please advise.

Thanks,
Mikael