autotools allows you to create a build system that will work on any system that has a shell
and make. that make may not be GNU make. it may have bugs. its feature set may be severely
limited compared to what you're used to. many projects out there who set out to write their
own build system do so using GNU make which means they write code that Works For Them.
non-portable GNU-isms creep in which means the build system is no longer portable to many
targets which sort of defeats the original intent: making it portable.