Make header include guards great again

runtime/bin/extensions.h

Index: runtime/bin/extensions.h
diff --git a/runtime/bin/extensions.h b/runtime/bin/extensions.h
index bcbcac3c7f834448bb0cc653814f8799e529ac32..3739c434f4e56180f4d99428722a34e1ca87f80a 100644
--- a/runtime/bin/extensions.h
+++ b/runtime/bin/extensions.h
@@ -2,8 +2,8 @@
 // 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.
 
-#ifndef BIN_EXTENSIONS_H_
-#define BIN_EXTENSIONS_H_
+#ifndef RUNTIME_BIN_EXTENSIONS_H_
+#define RUNTIME_BIN_EXTENSIONS_H_
 
 #include "include/dart_api.h"
 #include "platform/globals.h"
@@ -41,4 +41,4 @@ class Extensions {
 }  // namespace bin
 }  // namespace dart
 
-#endif  // BIN_EXTENSIONS_H_
+#endif  // RUNTIME_BIN_EXTENSIONS_H_