// Map _Ctype_* types to C.* types.
		err := func() error {
			txt, err := gofmtFile(f)
			if err != nil {
				return err
			}
			dir, err := os.MkdirTemp(os.TempDir(), "fix_cgo_typecheck")
			if err != nil {
				return err
			}
			defer os.RemoveAll(dir)
			err = os.WriteFile(filepath.Join(dir, "in.go"), txt, 0600)
			if err != nil {
				return err
			}
			goCmd := "go"