// by dist.
func writeHeader(w io.Writer) {
	fmt.Fprint(w, generatedHeader)
}

// mkzdefaultcc writes zdefaultcc.go:
//
//	package main
//	const defaultCC = <defaultcc>
//	const defaultCXX = <defaultcxx>
//	const defaultPkgConfig = <defaultpkgconfig>
//
// It is invoked to write cmd/go/internal/cfg/zdefaultcc.go
// but we also write cmd/cgo/zdefaultcc.go
func mkzdefaultcc(dir, file string) {

	// appropriate linker. In case of C++ code, use the compiler named
	// by the CXX environment variable or defaultCXX if CXX is not set.
	// Else, use the CC environment variable and defaultCC as fallback.
	var compiler []string
	if cxx {
		compiler = envList("CXX", cfg.DefaultCXX(cfg.Goos, cfg.Goarch))
	} else {
		compiler = envList("CC", cfg.DefaultCC(cfg.Goos, cfg.Goarch))
	}

	ccChanged := true
	if cc == "" {
		ccChanged = false
		cc = cfg.DefaultCC(cfg.Goos, cfg.Goarch)
	}
	cxx := cfg.Getenv("CXX")
	cxxChanged := true
	if cxx == "" {
		cxxChanged = false
		cxx = cfg.DefaultCXX(cfg.Goos, cfg.Goarch)
	}
	ar, arChanged := cfg.EnvOrAndChanged("AR", "ar")
	env = append(env, cfg.EnvVar{Name: "AR", Value: ar, Changed: arChanged})
	env = append(env, cfg.EnvVar{Name: "CC", Value: cc, Changed: ccChanged})

	goexperiment     string
	workdir          string
	tooldir          string
	oldgoos          string
	oldgoarch        string
	oldgocache       string
	exe              string
	defaultcc        map[string]string
	defaultcxx       map[string]string
	defaultpkgconfig string
	defaultldso      string

	rebuildall bool
	noOpt      bool
	isRelease  bool

	vflag int // verbosity
)

// The known architectures.

func (b *Builder) GccCmd(incdir, workdir string) []string {
	return b.compilerCmd(b.ccExe(), incdir, workdir)
}

// GxxCmd returns a g++ command line prefix
// defaultCXX is defined in zdefaultcc.go, written by cmd/dist.
func (b *Builder) GxxCmd(incdir, workdir string) []string {
	return b.compilerCmd(b.cxxExe(), incdir, workdir)
}