Display proper version information

- The cli version defaults to "unknown-version" unless set via the VERSION env var
- The commit version can be overridden via GITCOMMIT env var
- The build time can be overridden via BUILDTIME env var

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
Upstream-commit: cf51bde7d9
Component: cli

components/cli/scripts/build/binary

@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+
+source ./scripts/build/ldflags
+
+go build -o ./build/docker --ldflags "${LDFLAGS}" github.com/docker/cli/cmd/docker

components/cli/scripts/build/cross

@@ -0,0 +1,8 @@
+#!/usr/bin/env sh
+
+source ./scripts/build/ldflags
+
+gox -output build/docker-{{.OS}}-{{.Arch}} \
+    -osarch="linux/arm linux/amd64 darwin/amd64 windows/amd64" \
+	--ldflags "${LDFLAGS}" \
+	github.com/docker/cli/cmd/docker

components/cli/scripts/build/ldflags

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+VERSION=${VERSION:-"unknown-version"}
+GITCOMMIT=${GITCOMMIT:-$(git rev-parse --short HEAD 2> /dev/null || true)}
+BUILDTIME=${BUILDTIME:-$(date --utc --rfc-3339 ns 2> /dev/null | sed -e 's/ /T/')}
+
+export LDFLAGS="-X github.com/docker/cli/cli.GitCommit=${GITCOMMIT} \
+		-X github.com/docker/cli/cli.BuildTime=${BUILDTIME} \
+		-X github.com/docker/cli/cli.Version=${VERSION} ${LDFLAGS}"