func (tools gccgoToolchain) gccgoCleanPkgpath(b *Builder, p *load.Package) string {
	gccgoToSymbolFuncOnce.Do(func() {
		tmpdir := b.WorkDir
		if cfg.BuildN {
			tmpdir = os.TempDir()
		}
		fn, err := pkgpath.ToSymbolFunc(tools.compiler(), tmpdir)
		if err != nil {
			fmt.Fprintf(os.Stderr, "cmd/go: %v\n", err)
			base.SetExitStatus(2)
			base.Exit()
		}
		gccgoToSymbolFunc = fn
	})

		cmd := os.Getenv("GCCGO")
		if cmd == "" {
			cmd, err = exec.LookPath("gccgo")
			if err != nil {
				fatalf("unable to locate gccgo: %v", err)
			}
		}
		gccgoMangler, err = pkgpath.ToSymbolFunc(cmd, *objDir)
		if err != nil {
			fatalf("%v", err)
		}
	}
	return gccgoMangler(ppath)
}

// Return the package prefix when using gccgo.
func (p *Package) gccgoSymbolPrefix() string {