Enable to run build and invoke in background

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>

vendor/github.com/golang/protobuf/protoc-gen-go/main.go

@@ -0,0 +1,74 @@
+// Copyright 2010 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.
+
+// protoc-gen-go is a plugin for the Google protocol buffer compiler to generate
+// Go code. Install it by building this program and making it accessible within
+// your PATH with the name:
+//	protoc-gen-go
+//
+// The 'go' suffix becomes part of the argument for the protocol compiler,
+// such that it can be invoked as:
+//	protoc --go_out=paths=source_relative:. path/to/file.proto
+//
+// This generates Go bindings for the protocol buffer defined by file.proto.
+// With that input, the output will be written to:
+//	path/to/file.pb.go
+//
+// See the README and documentation for protocol buffers to learn more:
+//	https://developers.google.com/protocol-buffers/
+package main
+
+import (
+	"flag"
+	"fmt"
+	"strings"
+
+	"github.com/golang/protobuf/internal/gengogrpc"
+	gengo "google.golang.org/protobuf/cmd/protoc-gen-go/internal_gengo"
+	"google.golang.org/protobuf/compiler/protogen"
+)
+
+func main() {
+	var (
+		flags        flag.FlagSet
+		plugins      = flags.String("plugins", "", "list of plugins to enable (supported values: grpc)")
+		importPrefix = flags.String("import_prefix", "", "prefix to prepend to import paths")
+	)
+	importRewriteFunc := func(importPath protogen.GoImportPath) protogen.GoImportPath {
+		switch importPath {
+		case "context", "fmt", "math":
+			return importPath
+		}
+		if *importPrefix != "" {
+			return protogen.GoImportPath(*importPrefix) + importPath
+		}
+		return importPath
+	}
+	protogen.Options{
+		ParamFunc:         flags.Set,
+		ImportRewriteFunc: importRewriteFunc,
+	}.Run(func(gen *protogen.Plugin) error {
+		grpc := false
+		for _, plugin := range strings.Split(*plugins, ",") {
+			switch plugin {
+			case "grpc":
+				grpc = true
+			case "":
+			default:
+				return fmt.Errorf("protoc-gen-go: unknown plugin %q", plugin)
+			}
+		}
+		for _, f := range gen.Files {
+			if !f.Generate {
+				continue
+			}
+			g := gengo.GenerateFile(gen, f)
+			if grpc {
+				gengogrpc.GenerateFileContent(gen, f, g)
+			}
+		}
+		gen.SupportedFeatures = gengo.SupportedFeatures
+		return nil
+	})
+}