Add Makefile and bin/ scripts for one-command multi-arch release

make release builds, smoke-tests and pushes amd64 (on fsn1app1 via
DOCKER_HOST) and arm64 (local), joins them into latest and dated
multi-arch manifests, and commits the day's logs. Logic lives in bin/;
the Makefile only wires dependencies so -j2 runs the arches in parallel.

Makefile

@@ -0,0 +1,47 @@
+# Build and publish the base image. All logic lives in bin/; targets here
+# only wire dependencies and export configuration.
+#
+#   make release          build, test, push both arches, tag, commit logs
+#   make -j2 release      same, with the two arches in parallel
+#   make build            build for this machine's arch only
+#   make test             run the image smoke test for this machine's arch
+
+IMAGE  ?= git.eeqj.de/sneak/baseimage
+DATE   ?= $(shell date +%Y-%m-%d)
+ARCHES ?= amd64 arm64
+
+# Docker daemon to use per arch. Empty means the local daemon.
+DOCKER_HOST_amd64 ?= ssh://root@fsn1app1
+DOCKER_HOST_arm64 ?=
+
+NATIVE_ARCH := $(shell bin/native-arch)
+
+export IMAGE DATE ARCHES DOCKER_HOST_amd64 DOCKER_HOST_arm64
+
+.PHONY: release manifest commit-logs build test push clean \
+	$(ARCHES:%=build-%) $(ARCHES:%=test-%) $(ARCHES:%=push-%)
+
+release: commit-logs
+
+commit-logs: manifest
+	bin/commit-logs
+
+manifest: $(ARCHES:%=push-%)
+	bin/manifest
+
+# Static pattern rules: plain pattern rules are skipped for .PHONY targets.
+$(ARCHES:%=push-%): push-%: test-%
+	bin/push $*
+
+$(ARCHES:%=test-%): test-%: build-%
+	bin/test $*
+
+$(ARCHES:%=build-%): build-%:
+	bin/build $*
+
+build: build-$(NATIVE_ARCH)
+test: test-$(NATIVE_ARCH)
+push: push-$(NATIVE_ARCH)
+
+clean:
+	bin/clean