Using the technique from: https://github.com/resin-io-projects/armv7hf-debian-qemu

Wrap your build steps to taint the environment with qemu allowing building on x86_64.

RUN [ "cross-build-start" ]
RUN echo do build steps here
RUN [ "cross-build-end" ]

This leaves the container as a pure ARM container that could be pulled on a raspberry pi

You can get a bash shell with:

sudo docker run -it --entrypoint=/usr/bin/qemu-arm-static codingwell/rpi-raspbian-qemu /bin/bash