WebKit Hacking From the Bleeding Edge
As an open source project, I initially believed I could build and run WebKit wherever I choose. After all, isn’t that what “open source” is supposed to be all about? But ah, there’s a catch. At least when it comes to building and running WebKit on OS X releases, there is a dependency on a small, binary-only static library which provides key system-specific linkages to WebKit. Usually this binary is added to the open source project around the time the system release goes public, but not much sooner.
The long and short of it? If you want to build WebKit and you don’t work at Apple, you need to do so from publicly released versions of OS X.