internal: Fix LicenseComment not to use LICENSE file

internal/license.go

@@ -15,25 +15,30 @@
 package internal
 
 import (
-	"io/ioutil"
-	"path/filepath"
 	"regexp"
-	"runtime"
 	"strconv"
 	"strings"
 )
 
+const license = `Copyright 2013 The Ebiten 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.
+`
+
 // LicenseComment returns the license string in Go comment style.
 func LicenseComment() (string, error) {
-	_, path, _, _ := runtime.Caller(0)
-	licensePath := filepath.Join(filepath.Dir(path), "..", "LICENSE")
-	l, err := ioutil.ReadFile(licensePath)
-	if err != nil {
-		return "", err
-	}
-	lines := strings.Split(string(l), "\n")
-	license := "// " + strings.Join(lines[:len(lines)-1], "\n// ")
-	return license, nil
+	lines := strings.Split(license, "\n")
+	return "// " + strings.Join(lines[:len(lines)-1], "\n// "), nil
 }
 
 func LicenseYear() (int, error) {