Fix the archive code so that it compiles in a stricter mode.

utils/archive/messaging.h

 // 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.
 
 #ifndef DART_ARCHIVE_MESSAGING_H_
 #define DART_ARCHIVE_MESSAGING_H_
 
 #include "dart_archive.h"
 
 /**
@@ skipping 103 matching lines @@
  */
 Dart_CObject* getNullableStringArgument(Dart_Port p, Dart_CObject* request,
     int i);
 
 /**
  * Gets the string value of [object] or `NULL` if it's null. Note that this does
  * not validate the type of its argument.
  */
 char* getNullableString(Dart_CObject* object);
 
+/**
+ * Gets the module, name, and value, for a libarchive `set_option` function
+ * call. Returns whether or not the arguments were parsed correctly.
+ */
+bool getOptionArguments(Dart_Port p, Dart_CObject* request, char** module,
+    char** name, char** value);
+
 /** Declares a null [Dart_CObject] named [name]. */
 #define DART_NULL(name) \
   Dart_CObject name;    \
   name.type = kNull;
 
 /**
  * Declares a [Dart_CObject] bool named [name] with value [val].
  *
  * [val] should be a C boolean.
  */
@@ skipping 40 matching lines @@
 #define DART_STRING(name, val)  \
   Dart_CObject name;            \
   if (val == NULL) {            \
     name.type = kNull;          \
   } else {                      \
     name.type = kString;        \
     name.value.as_string = val; \
   }
 
 #endif  // DART_ARCHIVE_MESSAGING_H_