Thanks for clarifying the situation, Kovid.
It's true that I never mentioned here that I was modifying code. Otherwise I would have no reason to want to build Calibre, though.
A little backstory: I suggest Calibre to users of dslibris (
http://sourceforge.net/projects/ndslibris/), a book reader for the DS, since they need to use EPUB. Using Calibre myself on OS X, I started playing around with a prototype that follows the Apple idiom for the application menu. Having partially done that, I wanted to embed the changes into a bundle, without lookasides to a development area. So in this case it's no biggie to not be able to build an app bundle.
Now, I would sign on to documenting what the OS X build platform prerequisite is, and ways to possibly streamline it, but that would require some initial explanation from someone.
--cheers, ray