CMake was a step in the right direction, but it, too, suffers from thousands of under-documented options and fiddly behavior. In a former life I was tasked with maintaining a CMakeLists.txt for a project with multiple dependent libraries, binary blobs, open source dependencies that needed to get pulled in, and the whole thing had to be built for Windows, Linux, Mac, iOS, Android, and a handful of other lesser-known mobile platforms. I wouldn't wish that on my worst enemy.

It's not so bad. I have experience with two slightly different build systems based on CMake, which had to have customized toolchain definitions and build Cairo and WebKit. The Cairo build had a custom backend, which we integrated into Cairo's autotools. Cairo was driven using its autotools via CMake's "superproject" system.