return
		}
	} else {
		path := filepath.Join("testdata", zt.Name)
		if zt.Obscured {
			tf, err := obscuretestdata.DecodeToTempFile(path)
			if err != nil {
				t.Errorf("obscuretestdata.DecodeToTempFile(%s): %v", path, err)
				return
			}
			defer os.Remove(tf)
			path = tf
		}
		var rc *ReadCloser
		rc, err = OpenReader(path)
		if err == nil {
			defer rc.Close()

//
// The compiler command line is split into arguments on whitespace. Quotes
// are understood, so arguments may contain whitespace.
//
// checkGCCBaseCmd confirms that the compiler exists in PATH, returning
// an error if it does not.
func checkGCCBaseCmd() ([]string, error) {
	// Use $CC if set, since that's what the build uses.
	value := os.Getenv("CC")
	if value == "" {