Set of GNU tools that are known as the "Autotools".
Ranked in these QuestionsQuestion Ranking
Pro Based on standard tools
It's a standard tool built over standard tools.
It's a well established build system that is ubiquitous in the open source world.
Pro make distcheck
Build your project, run the tests, create a release tarball, unpack it with read-only sources, build it and run the tests. This should be the minimum standard for every build system, yet it seems hard to reach.
Pro Basic API for building anything: ./configure; make
The skills you learn for building one language still work when you build something else, even down to creating books for print from emacs org-mode.
Con Autotools is far too complicated
It seems to add far too much complexity to projects. The build system has a tendency to be more complex than the actual projects that it's being used to build.
Autoconf is dependent on Perl.
Con Poor documentation
In spite of its many years of existence, the available documentation leaves much to be desired.