I think a build system should always allow to convert its build description to a bash file that contains a more or less linear account of all actions needed (without support for incremental builds). Now if every library were distributed with such linear script, the user is guaranteed not to get stuck in obscure build problems. And of course, they can first try the official incremental route (cmake in this case) if they like.
Most of the build issues that a user will face is there system not matching the developers.
We can have pretty complicated logic (arbitrary logic in most build systems) for probing the build system, and much of this logic will inevitably get lost when compiling a linear script.
Once you put all of the complexity in the compiled script, I don't think you've gained anything over "make clean ; make" (or equivelent)
