add shellspec golden harness for the legacy make engine

- spec/golden/cases.txt: 69 black-box cases (CLI wrapper mode and make
  include mode) run in a hermetic sandbox with a mocked docker
- spec/golden/expected/*.txt recorded from this engine (baseline)
- make test / test-golden / golden-record / lint dev targets

spec/fixtures/host-project/stack/host/consul.yml

@@ -0,0 +1,12 @@
+services:
+  consul:
+    image: hashicorp/consul:1.15
+    container_name: ${HOST_COMPOSE_PROJECT_NAME:-localhost}-consul
+    network_mode: host
+    restart: always
+    environment:
+      CONSUL_HTTP_TOKEN: ${HOST_CONSUL_HTTP_TOKEN}
+    volumes:
+      - consul:/consul/data
+volumes:
+  consul:

spec/fixtures/host-project/stack/host/fabio.yml

@@ -0,0 +1,13 @@
+services:
+  fabio:
+    image: fabiolb/fabio:1.6.3
+    container_name: ${HOST_COMPOSE_PROJECT_NAME:-localhost}-fabio
+    depends_on: [consul]
+    ports:
+      - "80:80"
+      - "443:443"
+    environment:
+      FABIO_REGISTRY_CONSUL_ADDR: ${DOCKER_HOST_INET4:-127.0.0.1}:8500
+      FABIO_LOG_ACCESS_TARGET: ${HOST_FABIO_LOG_ACCESS:-}
+    networks:
+      - public

spec/fixtures/host-project/stack/host/host.mk

@@ -0,0 +1,10 @@
+# Stack host: consul + fabio (80/443) + registrator, one instance per host.
+host                            ?= host/consul host/fabio host/registrator
+
+.PHONY: host
+host:
+	$(call make,up STACK="$(host)")
+
+.PHONY: host-down
+host-down:
+	$(call make,down STACK="$(host)")

spec/fixtures/host-project/stack/host/registrator.yml

@@ -0,0 +1,9 @@
+services:
+  registrator:
+    image: gliderlabs/registrator:master
+    container_name: ${HOST_COMPOSE_PROJECT_NAME:-localhost}-registrator
+    network_mode: host
+    depends_on: [consul]
+    command: -internal=false -useIpFromLabel SERVICE_ADDRESS consul://127.0.0.1:8500
+    volumes:
+      - ${DOCKER_SOCKET_LOCATION:-/var/run/docker.sock}:/tmp/docker.sock