Requirements:

Download the Android NDK:

Install dependencies for cross-compiling:

sudo apt update
sudo apt install -y \
    autoconf \
    automake \
    bison \
    bc \
    build-essential \
    clang \
    cpio \
    cmake \
    cmake-format \
    curl \
    debhelper \
    debhelper-compat \
    device-tree-compiler \
    dpkg-dev \
    dwarves \
    file \
    fakeroot \
    flex \
    g++ \
    g++-multilib \
    git \
    gawk \
    gettext \
    libdb-dev \
    libelf-dev \
    libffi-dev \
    libgmp-dev \
    liblzma-dev \
    libmpc-dev \
    libmpfr-dev \
    libncurses-dev \
    libncurses5-dev \
    libssl-dev \
    libtool \
    make \
    ninja-build \
    patch \
    pkg-config \
    python3 \
    python3-pip \
    python3-setuptools \
    rsync \
    unzip \
    wget \
    xsltproc \
    zip \
    zlib1g-dev