I've changed the way we build, and in the process made things (temporarily, I hope) a lot less cross-platform. Rather than doing our own dance, I've switched everything to use rake-compiler (rake/extensiontask), which removed a lot of code. I've also removed anything related to platforms or cross-compilation: The build assumes Mac OS X, though it might work on other Unixish systems. Wider support will be back at some point.
I'm deleting a lot of good stuff here, including Johnson.Template, Yehuda's work on page DOM, and the jQuery tests. I don't think they belong in Johnson proper. We'll likely move a lot of the page DOM stuff to Aaron's work on Taka.