The elephant in the room is that the hybrid Autotools + btool system is more hassle than it's worth.
The options we have are: 1. CMake, which has a scripting language so weak and verbose that it's insulting, but a lot of people use it. 2. Waf, which gives you the full expressive power of Python, but the maintainer has some ideas which make me question the long term viability of the project. 3. Our own fork of Waf that removes the maintainer problem, but ties up manpower. 4. SCons, which is also Pythonic, but slow as molasses.
There is a version of Inkscape that builds with a modified copy of Waf available at lp:~tweenk/inkscape/waf-build. The source to the modified copy of Waf is at lp:inkwaf. The amount of code in Waf scripts, compared to the existing body of Automake/Autoconf code, is rather modest.
Regards, Krzysztof