return v, changed
	}
	return def, false
}

var SumdbDir = gopathDir("pkg/sumdb")

// GetArchEnv returns the name and setting of the
// GOARCH-specific architecture environment variable.
// If the current architecture has no GOARCH-specific variable,
// GetArchEnv returns empty key and value.
func GetArchEnv() (key, val string, changed bool) {
	switch Goarch {
	case "arm":
		return "GOARM", GOARM, goARMChanged

		env = append(env, cfg.EnvVar{Name: "GCCGO", Value: work.GccgoBin, Changed: true})
	} else {
		env = append(env, cfg.EnvVar{Name: "GCCGO", Value: work.GccgoName})
	}

	goarch, val, changed := cfg.GetArchEnv()
	if goarch != "" {
		env = append(env, cfg.EnvVar{Name: goarch, Value: val, Changed: changed})
	}

	cc := cfg.Getenv("CC")
	ccChanged := true
	if cc == "" {
		ccChanged = false

		if len(p.SFiles) > 0 {
			fmt.Fprintf(h, "asm %q %q %q\n", b.toolID("asm"), forcedAsmflags, p.Internal.Asmflags)
		}

		// GOARM, GOMIPS, etc.
		key, val, _ := cfg.GetArchEnv()
		fmt.Fprintf(h, "%s=%s\n", key, val)

		if cfg.CleanGOEXPERIMENT != "" {
			fmt.Fprintf(h, "GOEXPERIMENT=%q\n", cfg.CleanGOEXPERIMENT)
		}

	appendSetting("GOARCH", cfg.BuildContext.GOARCH)
	if cfg.RawGOEXPERIMENT != "" {
		appendSetting("GOEXPERIMENT", cfg.RawGOEXPERIMENT)
	}
	appendSetting("GOOS", cfg.BuildContext.GOOS)
	if key, val, _ := cfg.GetArchEnv(); key != "" && val != "" {
		appendSetting(key, val)
	}

	// Add VCS status if all conditions are true:
	//
	// - -buildvcs is enabled.