title: Proper way to make a fat binary prefer to be 32bit on 64bit OS X 10.6?
body: <p>Suppose I ask the user "do you want to run in 32bit mode or 64bit mode" and they pick 32bit.  How do I register this fact with the operating system?  I've looked at the <a href="http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man1/arch.1.html" rel="nofollow noreferrer">arch</a> command, but I don't want to have to write a script that wraps the binary.  I suspect there is a plist-y way to do this, but I can't find documentation (other than arch).</p>