It seems that Xorg, as of the 7.0 release, has been split into monolithic and modular development trees. The modular model allows you to compile individual components related to Xorg separately from the whole X server, so that you don’t need to do a two-hour compilation just to work on this or that driver or this or that library.
This is good news for me. My biggest craving lately was to put my C skills to use by diving into a big project that has effects on the Linux desktop, and Xorg is certainly the biggest in that sense. However, in the past I was always put off by the huge amount of groking one needs to do just to understand the Xorg compilation process. After class is over, I’m gonna start diving in.