How to compile CoreAudio PlayFile sample code for 64 bit?

This is a newbie CoreAudio question. I downloaded Apple's PlayFile sample code. If I use the provided Xcode project, it builds it as 32 bit, passing -arch i386 to the compiler. If I build from the command line and and pass -arch i386 it still all works fine, but if I remove that flag or change it to -arch x86_64, the program dies on AUOpenGraph with an error code of -2005 (badComponen开发者_StackOverflowtType).

How do I compile it as a 64 bit program? I'd like to know just the flags to pass to clang or gcc.