Let breakpad build with -Wall on OS X and Linux.

src/common/linux/libcurl_wrapper.h

 // Copyright (c) 2009, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 25 matching lines @@
 #include <string>
 #include <map>
 
 #include "common/using_std_string.h"
 #include "third_party/curl/curl.h"
 
 namespace google_breakpad {
 class LibcurlWrapper {
  public:
   LibcurlWrapper();
-  ~LibcurlWrapper();
+  virtual ~LibcurlWrapper();
   virtual bool Init();
   virtual bool SetProxy(const string& proxy_host,
                         const string& proxy_userpwd);
   virtual bool AddFile(const string& upload_file_path,
                        const string& basename);
   virtual bool SendRequest(const string& url,
                            const std::map<string, string>& parameters,
                            int* http_status_code,
                            string* http_header_data,
                            string* http_response_data);
@@ skipping 27 matching lines @@
   CURLcode (*easy_perform_)(CURL *);
   const char* (*easy_strerror_)(CURLcode);
   void (*easy_cleanup_)(CURL *);
   CURLcode (*easy_getinfo_)(CURL *, CURLINFO info, ...);
   void (*formfree_)(struct curl_httppost *);
 
 };
 }
 
 #endif  // COMMON_LINUX_LIBCURL_WRAPPER_H_