Build script detects macOS and runs itself under docker

build.sh

#!/usr/bin/env bash

cd "$(dirname "$0")/.."
if [[ "$(uname)" == "Darwin" ]]; then
  docker build --tag foo-rpmbuild .
  docker run --interactive --tty --rm \
    --volume "${PWD}:/opt/docker-host" \
    --volume "$(yarn cache dir | grep '^/'):/var/run/yarn-cache" \
    foo-rpmbuild /opt/docker-host/bin/build.sh
  exit
fi