golang mac_noasm 代码
文件路径：/src/vendor/golang.org/x/crypto/internal/poly1305/mac_noasm.go
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build (!amd64 && !ppc64le && !s390x) || !gc || purego
// +build !amd64,!ppc64le,!s390x !gc purego
package poly1305
type mac struct{ macGeneric }