I would like to contribute bmake. Also present in Debian, Fedora, 
FreeBSD, Ubuntu, ...

I occasionally use it to check whether Makefiles are compatible with 
non-GNU versions of make.

SUMMARY="Portable version of the NetBSD 'make' utility"

DESCRIPTION="\
bmake is a portable version of the NetBSD make(1) utility.  It is similar
to GNU make, even though the syntax for the advanced features supported
in Makefiles is very different."

bmake_extras_SUMMARY="${SUMMARY} (additional support files)"

bmake_extras_DESCRIPTION="${DESCRIPTION}
This package contains many additional *.mk files and some support scripts
which are only required if used in Makefiles."

bmake-20240301-1.tar.xz:
usr/bin/bmake.exe
usr/share/doc/bmake/*
usr/share/man/man1/bmake.1.gz
usr/share/bmake/mk/host-target.mk
usr/share/bmake/mk/suffixes.mk
usr/share/bmake/mk/sys.mk
usr/share/bmake/mk/sys.*.mk
usr/share/bmake/mk/sys/Generic.mk

bmake-extras-20240301-1.tar.xz:
usr/share/bmake/mk/*.mk
usr/share/bmake/mk/install-sh
usr/share/bmake/mk/meta2deps.py
usr/share/bmake/mk/meta2deps.sh
usr/share/bmake/mk/mkopt.sh
usr/share/bmake/mk/stage-install.sh
usr/share/bmake/mk/sys/*.mk

-- 
Regards,
Christian