Install this version:
emerge -a =app-emacs/poly-gams-20260831.625
If this version is masked, you can unmask it using the autounmask tool or standard emerge options:
autounmask =app-emacs/poly-gams-20260831.625
Or alternatively:
emerge --autounmask-write -a =app-emacs/poly-gams-20260831.625
# automatically generated by g-sorcery
# please do not edit this file
EAPI=8
REPO_URI="https://melpa.org/packages/"
SOURCE_TYPE="tar"
REALNAME="poly-gams"
DIGEST_SOURCES="yes"
inherit g-sorcery gs-elpa
DESCRIPTION="Polymode for GAMS"
HOMEPAGE="https://github.com/ShiroTakeda/poly-gams"
SRC_URI="${REPO_URI}${REALNAME}-${PV}.${SUFFIX}"
SLOT="0"
KEYWORDS="~amd64 ~x86"
DEPEND="app-emacs/polymode
app-emacs/gams-mode"
RDEPEND="app-emacs/polymode
app-emacs/gams-mode"
app-emacs/polymode app-emacs/gams-mode
app-emacs/polymode app-emacs/gams-mode