how to include build information in the executable [golang] [makefile]

main.go

package main

import "fmt"

var (
	buildBranch      = "UNKNOWN"
	buildCommit      = "UNKNOWN"
	buildCommitShort = "UNKNOWN"
	buildDate        = "UNKNOWN"
	buildRepo        = "UNKNOWN"
	buildVersion     = "UNKNOWN"
)

func main() {
	fmt.Println("branch:", buildBranch)
	fmt.Println("commit:", buildCommit)
	fmt.Println("commit short:", buildCommitShort)
	fmt.Println("build time:", buildDate)
	fmt.Println("repo:", buildRepo)
	fmt.Println("version:", buildVersion)
}

Makefile

.PHONY: init
init: .git

.git:
	@echo ">>> Git initialization: Start"
	@git init
	@git remote add origin git@github.com:mtilson/gist-example.git
	@git add .
	@git commit -m "init"
	@git tag v0.1.0
	@echo ">>> Git initialization: Finished"
	@echo

.PHONY: build
build: init
	@go build -ldflags \
		"-X main.buildBranch=${shell git rev-parse --abbrev-ref HEAD} \
		 -X main.buildCommit=${shell git rev-parse HEAD} \
		 -X main.buildCommitShort=${shell git rev-parse --short HEAD} \
		 -X main.buildDate=${shell date -u +%Y%m%d.%H%M%S} \
		 -X main.buildRepo=${shell git config --get remote.origin.url} \
		 -X main.buildVersion=${shell git describe --tags}" \
		main.go

.PHONY: run
run: clean build
	@echo ">>> Application: Start"
	@./main
	@echo ">>> Application: Finished"

.PHONY: clean
clean:
	@rm -f ./main

.DEFAULT_GOAL := run