Make dart2js executable.

dart/utils/compiler/build_helper.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #import('dart:io');
 #import('dart:uri');
 
 main() {
   List<String> arguments = new Options().arguments;
   Uri uri = new Uri(scheme: 'file', path: '${arguments[0]}/');
@@ skipping 11 matching lines @@
 }
 
 writeScript(Uri uri, List<String> chunks) {
   var f = new File(uri.path);
   var stream = f.openSync(FileMode.WRITE);
   for (String chunk in chunks) {
     stream.writeStringSync(chunk);
   }
   stream.closeSync();
 
-  // TODO(ahe): Make script executable.
   // TODO(ahe): Also make a .bat file for Windows.
+
+  if (new Platform().operatingSystem() != 'windows') {
+    onExit(int exitCode, String stdout, String stderr) {
+      if (exitCode != 0) {
+        print(stdout);
+        print(stderr);
+        exit(exitCode);
+      }
+    }
+    new Process.run('/bin/chmod', ['+x', uri.path], null, onExit);
+  }
 }
 
 buildScript(Uri uri) {
+  String dart2jsPath =
+      uri.resolve('../../lib/compiler/implementation/dart2js.dart').path;
+  String libraryRoot = uri.resolve('../../').path;
   return """
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file

[kasperl, 2012/04/17 15:19:39]

Would it make sense to throw this string into a top-level named constant so that
the indentation seems less off?

[ahe, 2012/04/17 16:08:15]

I'm using string interpolation. The best I can do is put it in a toplevel
method.

+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
 
 #import('dart:io');
 
-#import('${uri.resolve('../../lib/compiler/implementation/dart2js.dart').path}');
+#import('$dart2jsPath');
 
 class Helper {
   void run() {
     try {
-      List<String> argv = ['--library-root=${uri.resolve('../../').path}'];
+      List<String> argv = ['--library-root=$libraryRoot'];
       argv.addAll(new Options().arguments);
       compile(argv);
     } catch (var exception, var trace) {
       try {
         print('Internal error: \$exception');
       } catch (var ignored) {
         print('Internal error: error while printing exception');
       }
       try {
         print(trace);
       } finally {
         exit(253); // 253 is recognized as a crash by our test scripts.
       }
     }
   }
 }
 
 void main() {
   new Helper().run();
 }
 """;
 }