GO111MODULE
		Controls whether the go command runs in module-aware mode or GOPATH mode.
		May be "off", "on", or "auto".
		See https://golang.org/ref/mod#mod-commands.
	GCCGO
		The gccgo command to run for 'go build -compiler=gccgo'.
	GOARCH
		The architecture, or processor, for which to compile code.
		Examples are amd64, 386, arm, ppc64.
	GOBIN
		The directory where 'go install' will install a command.
	GOCACHE

	}
	js = append(js, '\n')
	if err := sh.writeFile(a.Objdir+"vet.cfg", js); err != nil {
		return err
	}

	// TODO(rsc): Why do we pass $GCCGO to go vet?
	env := b.cCompilerEnv()
	if cfg.BuildToolchainName == "gccgo" {
		env = append(env, "GCCGO="+BuildToolchain.compiler())
	}

	p := a.Package
	tool := VetTool
	if tool == "" {
		tool = base.Tool("vet")
	}

//
//	GO111MODULE
//		Controls whether the go command runs in module-aware mode or GOPATH mode.
//		May be "off", "on", or "auto".
//		See https://golang.org/ref/mod#mod-commands.
//	GCCGO
//		The gccgo command to run for 'go build -compiler=gccgo'.
//	GOARCH
//		The architecture, or processor, for which to compile code.
//		Examples are amd64, 386, arm, ppc64.
//	GOBIN