hack: base build scripts

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

hack/dockerfiles/lint.Dockerfile

@@ -0,0 +1,10 @@
+# syntax=docker/dockerfile:1.0-experimental
+
+FROM golang:1.12-alpine
+RUN  apk add --no-cache git
+RUN  go get -u gopkg.in/alecthomas/gometalinter.v1 \
+  && mv /go/bin/gometalinter.v1 /go/bin/gometalinter \
+  && gometalinter --install
+WORKDIR /go/src/github.com/moby/buildkit
+RUN --mount=target=/go/src/github.com/tonistiigi/buildx \
+	gometalinter --config=gometalinter.json ./...

hack/dockerfiles/vendor.Dockerfile

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+# syntax = docker/dockerfile:1.0-experimental
+FROM golang:1.12-alpine AS vendored
+RUN  apk add --no-cache git
+WORKDIR /src
+RUN --mount=target=/src,rw \
+  --mount=target=/go/pkg/mod,type=cache \
+  go mod tidy && go mod vendor && \
+  mkdir /out && cp -r go.mod go.sum vendor /out
+
+FROM scratch AS update
+COPY --from=vendored /out /out
+
+FROM vendored AS validate
+RUN --mount=target=.,rw \
+  git add -A && \
+  rm -rf vendor && \
+  cp -rf /out/* . && \
+  ./hack/validate-vendor check