[Arelius]

Darwin itself uses very little BSD code. It's built on Mach. OS X does however import much of the BSD userland, but I don't even know if much of that makes it into iOS.

I think it'd be a fair guess to say that iOS likely contains very little BSD Unix code.

[mdwrigh2]

For what it's worth, Android also uses a lot of BSD userspace code (see toolbox).