Add auto-qemu logic

mastodon/build.sh

@@ -52,6 +52,11 @@ function build_image() {
 
 require "$VERSION" "version"
 
+if ! docker run --rm -it arm64v8/ubuntu:19.10 /bin/bash -c 'echo "docker is configured correctly"'; then
+    echo "docker is not configured to run on qemu-emulated architectures, fixing will require sudo"
+    sudo docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+fi
+
 set -xe
 
 build_image asonix/mastodon arm64v8