x86_64 and x86 userland

[Ralf Wildenhues]

I have a question regarding systems with more than one ABI, specifically
x86_64.  If you consider for example the Debian distribution which has a
x86_64 kernel, but a completely x86 userland, config.guess still gives
you x86_64-unknown-linux-gnu as output.  (I have been told this, but not
tried it myself).

Now, if you configure a package and forget to add
  --build=i686-pc-linux-gnu
or maybe use the setarch tool to set personality (I do not even know how
portable/available this is -- it exists in RedHat Fedora), it may break,
e.g. because of the __x86_64__ preprocessor define.

Would it not make more sense to have config.guess return i686 instead of
x86_64?  Is it just too late to make that change now?  How would it even
be possible to detect a completely 32bit userland?

Should I rather ask this on the config-patches list or elsewhere?

Regards,
Ralf