use va_start, not [_]_crt_va_start

sandbox/win/sandbox_poc/main_ui_window.cc

 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <windows.h>
 #include <CommCtrl.h>
 #include <commdlg.h>
+#include <stdarg.h>
 #include <time.h>
 #include <windowsx.h>
 #include <atlbase.h>
 #include <atlsecurity.h>
 #include <algorithm>
 #include <sstream>
 
 #include "sandbox/win/sandbox_poc/main_ui_window.h"
 #include "base/logging.h"
 #include "sandbox/win/sandbox_poc/resource.h"
@@ skipping 599 matching lines @@
 }
 
 void MainUIWindow::AddDebugMessage(const wchar_t* format, ...) {
   DCHECK(format);
   if (!format)
     return;
 
   const int kMaxDebugBuffSize = 1024;
 
   va_list arg_list;
-#if _MSC_VER >= 1900
-  __crt_va_start(arg_list, format);
-#else
-  _crt_va_start(arg_list, format);
-#endif
+  va_start(arg_list, format);
 
   wchar_t text[kMaxDebugBuffSize + 1];
   vswprintf_s(text, kMaxDebugBuffSize, format, arg_list);
   text[kMaxDebugBuffSize] = L'\0';
 
   InsertLineInListView(text);
 }
 
 
 void MainUIWindow::InsertLineInListView(wchar_t* debug_message) {
@@ skipping 22 matching lines @@
   item.iItem = ListView_GetItemCount(list_view_);
   item.iSubItem = 0;
   item.mask = LVIF_TEXT | LVIF_PARAM;
   item.pszText = message_time;
   item.lParam = 0;
 
   ListView_InsertItem(list_view_, &item);
 
   delete[] message_time;
 }