Add gitcommit to runc builds

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

Makefile

@@ -5,16 +5,17 @@ TEST_DOCKERFILE=script/test_Dockerfile
 BUILDTAGS=seccomp
 RUNC_BUILD_PATH=/go/src/github.com/opencontainers/runc/runc
 RUNC_INSTANCE=runc_dev
+COMMIT=$(shell git rev-parse HEAD 2> /dev/null || true)
 export GOPATH:=$(CURDIR)/Godeps/_workspace:$(GOPATH)
 
 .PHONY=dbuild
 
 all:
 	ln -sfn $(CURDIR) $(CURDIR)/Godeps/_workspace/src/github.com/opencontainers/runc
-	go build -tags "$(BUILDTAGS)" -o runc .
+	go build -ldflags "-X main.gitCommit=${COMMIT}" -tags "$(BUILDTAGS)" -o runc .
 
 static:
-	CGO_ENABLED=1 go build -tags "$(BUILDTAGS) cgo static_build" -ldflags "-w -extldflags -static" -o runc .
+	CGO_ENABLED=1 go build -tags "$(BUILDTAGS) cgo static_build" -ldflags "-w -extldflags -static -X main.gitCommit=${COMMIT}" -o runc .
 
 vet:
 	go get golang.org/x/tools/cmd/vet

main.go

@@ -3,12 +3,17 @@ package main
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	"github.com/Sirupsen/logrus"
 	"github.com/codegangsta/cli"
 	"github.com/opencontainers/specs/specs-go"
 )
 
+// gitCommit will be the hash that the binary was built from
+// and will be populated by the Makefile
+var gitCommit = ""
+
 const (
 	version    = "0.0.9"
 	specConfig = "config.json"
@@ -41,7 +46,14 @@ func main() {
 	app := cli.NewApp()
 	app.Name = "runc"
 	app.Usage = usage
-	app.Version = fmt.Sprintf("%s\nspec version %s", version, specs.Version)
+	v := []string{
+		version,
+	}
+	if gitCommit != "" {
+		v = append(v, fmt.Sprintf("commit: %s", gitCommit))
+	}
+	v = append(v, fmt.Sprintf("spec: %s", specs.Version))
+	app.Version = strings.Join(v, "\n")
 	app.Flags = []cli.Flag{
 		cli.BoolFlag{
 			Name:  "debug",