Alpine Package Keeper (apk) is a package manager originally built for Alpine Linux, but now used by several other distributions as well.
The preferred build system for building apk-tools is Meson:
# meson setup -Dprefix=/ build
# ninja -C build
# meson install -C build
For bootstrapping without Python, muon is also compatible. All you have to do is replace meson with muon in the above example.
To build a static apk, pass the right arguments to the above commands:
# meson setup -Dc_link_args="-static" -Dprefer_static=true -Ddefault_library=static build
# ninja -C build src/apk
Which will give you a ./build/src/apk that is statically linked.
While there is a legacy Makefile-based system available, it only works for musl-linux targets, and will be dropped in the apk-tools 3.0 release.
Online documentation is available in the doc/ directory in the form of man pages.
The apk(8) man page provides a basic overview of the package management system.