tools: Move and rename kernel-compile container

Move it to tools and renamed it to kernel-compile, similar to
c-compile and go-compile.

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

tools/kernel-compile/Dockerfile

@@ -0,0 +1,23 @@
+FROM alpine:3.5
+RUN \
+  apk update && apk upgrade && \
+  apk add \
+  build-base \
+  argp-standalone \
+  automake \
+  bash \
+  bc \
+  binutils-dev \
+  curl \
+  git \
+  gmp-dev \
+  installkernel \
+  kmod \
+  libelf-dev \
+  linux-headers \
+  ncurses-dev \
+  sed \
+  squashfs-tools \
+  tar \
+  xz \
+  && true

tools/kernel-compile/Makefile

@@ -0,0 +1,29 @@
+.PHONY: tag push
+
+BASE=alpine:3.5
+IMAGE=kernel-compile
+
+default: push
+
+hash:
+	DOCKER_CONTENT_TRUST=1 docker pull $(BASE)
+	tar cf - Dockerfile | docker build --no-cache -t $(IMAGE):build -
+	docker run --rm $(IMAGE):build sha1sum /lib/apk/db/installed | sed 's/ .*//' > hash
+
+push: hash
+	docker pull linuxkit/$(IMAGE):$(shell cat hash) || \
+		(docker tag $(IMAGE):build linuxkit/$(IMAGE):$(shell cat hash) && \
+		 docker push linuxkit/$(IMAGE):$(shell cat hash))
+	docker rmi $(IMAGE):build
+	rm -f hash
+
+tag: hash
+	docker pull linuxkit/$(IMAGE):$(shell cat hash) || \
+		docker tag $(IMAGE):build linuxkit/$(IMAGE):$(shell cat hash)
+	docker rmi $(IMAGE):build
+	rm -f hash
+
+clean:
+	rm -f hash
+
+.DELETE_ON_ERROR: