Specify package to build only on a single architecture?

["Steve M. Robbins" <steve@sumost.ca>]

Hi,

I have a package that is only useful on 1 architecture.  How is that stated in 
the control file?  I tried putting "Architecture" in the initial paragraph but 
the build complains:

dpkg-source: warning: unknown information field 'Architecture' in input data in 
general section of control info file

What's the mechanism for this?

Thanks,
-Steve