Install this version:
emerge -a =app-emacs/commander-9999
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask =app-emacs/commander-9999
Or alternatively:
emerge --autounmask-write -a =app-emacs/commander-9999
# Copyright 1999-2021 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2
EAPI=8
NEED_EMACS="24"
MY_PN="${PN}.el"
MY_P="${MY_PN}-${PV}"
inherit elisp git-r3
DESCRIPTION="Emacs command line parser"
HOMEPAGE="https://github.com/rejeep/commander.el"
EGIT_REPO_URI="https://github.com/rejeep/${MY_PN}.git"
KEYWORDS="~amd64 ~x86"
LICENSE="GPL-3"
SLOT="0"
DOCS="README.md"
RDEPEND="
>=app-emacs/dash-2.0.0
>=app-emacs/f-0.6.1
>=app-emacs/s-1.6.0
"