# This Docker image can change from one build to another, because the upstream
# Debian/Ubuntu package index is continuously updated and we have to run
# `apt-get update` in here.
#
# The only way to make this a part of our reproducible build system is to build
# it once, upload it to Docker Hub and make sure it's being pulled regularly so
# it's not deleted after 6 months of inactivity.

FROM ubuntu:21.04

SHELL ["/bin/bash", "-c"]

ENV DEBIAN_FRONTEND=noninteractive TZ="Etc/UTC"
RUN apt-get -qq update \
 && apt-get -qq -y install build-essential git curl \
  libc6-armhf-armel-cross libc6-dev-armel-armhf-cross binutils-arm-linux-gnueabihf \
  gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf &>/dev/null \
 && apt-get -qq clean \
 && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*