fix darwin_arm64 build.

global/codec/codec.go

@@ -1,4 +1,4 @@
-// +build linux windows,!arm darwin
+// +build linux windows,!arm darwin,!arm64
 // +build 386 amd64 arm arm64
 
 // Package codec Slik编码核心模块

global/codec/codec_darwin_arm64.go

@@ -0,0 +1,8 @@
+package codec
+
+import "github.com/pkg/errors"
+
+//EncodeToSilk 将音频编码为Silk
+func EncodeToSilk(record []byte, tempName string, useCache bool) ([]byte, error) {
+	return nil, errors.New("not supported now")
+}