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 Poor documentation
In spite of its many years of existence, the available documentation leaves much to be desired.
Autoconf is dependent on Perl.