> > Makefiles generated by automake are more feature rich in general, > which is understandable as its the only backend it has to support.
The main problem here - Postrges do not use automake at all! Postgres it's autoconf + handmade GNU Make files + perl script for generating old MSVC project from this Makefiles. "make distcheck" > CMake have no this bad concept, in my opinion, if you want to make the project you should have a full build environment. (but I don't want to argue about it here) Also, as I wrote before, CMake it's not equivalent of GNU Make or Autoconf, many your reasons based on that fact what CMake, is not a build system it's more like project generation system. And anyway, you have no option if you want to support Windows without pain and much more hacks ways.
