Generate libvirt constants from libvirt sources.

- Add a yacc-based parser and a hand-written lexer to read the
remote_protocol.x file from libvirt's sources.
- Use the new parser to generate the constants used to communicate with
libvirt.

internal/lvgen/gen/main.go

@@ -0,0 +1,43 @@
+// Copyright 2017 The go-libvirt Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path"
+
+	"github.com/digitalocean/go-libvirt/internal/lvgen"
+)
+
+// TODO: make these an argument
+const lvPath = "../../../libvirt"
+const protoPath = "src/remote/remote_protocol.x"
+
+func main() {
+	fmt.Println("Generating golang bindings for libvirt")
+	lvFile := path.Join(lvPath, protoPath)
+	rdr, err := os.Open(lvFile)
+	if err != nil {
+		fmt.Printf("failed to open protocol file at %v: %v\n", lvFile, err)
+		os.Exit(1)
+	}
+	defer rdr.Close()
+
+	if err = lvgen.Generate(rdr); err != nil {
+		fmt.Println("go-libvirt code generator failed:", err)
+		os.Exit(1)
+	}
+}