Starting from an Ubuntu installation or similar Docker image, install the NDK.
curl -s -o /tmp/android-ndk.zip https://dl.google.com/android/repository/android-ndk-r14b-linux-x86_64.zip
cd /usr/local
unzip /tmp/android-ndk.zip
rm -f /tmp/android-ndk.zip
Create the standalone stuff, whatever that is. Arm and arm64.