Variables

ACCEPT_KEYWORDS="~amd64"
EPREFIX="/data/data/com.termux/files/home/.local/var/tmp/gentoo"
PROFILE_PATH="/usr/portage/profiles/default/linux/arm/17.0/armv7a/prefix"

LD_PRELOAD="${EPREFIX}/lib/libc.so.6"
PATH="${PATH}:${EPREFIX}/usr/bin"
$EPREFIX/usr/bin/gcc -v

Output from bootstrap-rap.sh

Ok, I'm going to do a little bit of guesswork here.  Thing is, your
machine appears to be identified by CHOST=armv7l-pc-linux-gnu

Termux Dependencies

pkg install clang autoconf libtool

Installing Portage

git clone https://github.com/gentoo/portage

References:

• Gentoo Project:Android/build

• Gentoo Wiki: Embedded Handbook - Cross-compiling with Portage

• Termux Wiki: Package Management