Feature request #1641: Build preference panel as universal (32/64-bit)

Not sure whether this would be worth it, but this would allow us to go back to being a System Preferences-hosted panel.

Would need a 32-bit version that uses retain/release, and a 64-bit version which uses GC.

References:

• http://www.cocoarocket.com/articles/sysprefpanes.html
• http://www.suffix.be/blog/building-64bit-prefpane/
• http://osx-files.net/news/?p=142

On Leopard, the System Preferences application is 32-bit application that does not use Garbage Collection.

On Snow Leopard only, it continues to be a 32-bit, non-GC application, but also provides a 64-bit version which does use GC.

Like I said, not sure if this is worth the hassle, seeing as we are currently building as 32-bit GC, but it is worth thinking about it.