This still requires xmake to be installed. CMake does that too, as does Premake and a bunch of other tools, but they all need to be installed - except Autotools.
What i'm talking about is generating a script for something that is part of the OS itself (like shell script, which is what Autotools does) that itself generates the Makefile which uses a widely available standard tool (Make). So a user (i include library users - as opposed to library developers - as "users" here) wont need to install xmake/cmake/whatever just to build the program/library, they only need to have shell and make which are available everywhere. On Unix at least, on Windows it'd need to generate a batch file for MSVC (this is where Autotools fall short since they're made for unix only).