Fix preparing log file name.

src/base/platform/platform-win32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Platform-specific code for Win32.
 
 // Secure API functions are not available using MinGW with msvcrt.dll
 // on Windows XP. Make sure MINGW_HAS_SECURE_API is not defined to
 // disable definition of secure API functions in standard headers that
 // would conflict with our own implementation.
@@ skipping 557 matching lines @@
     return NULL;
   }
 }
 
 
 bool OS::Remove(const char* path) {
   return (DeleteFileA(path) != 0);
 }
 
 
+bool OS::isDirectorySeparator(const char ch) {
+  return ch == '/' || ch == '\\';
+}
+
+
 FILE* OS::OpenTemporaryFile() {
   // tmpfile_s tries to use the root dir, don't use it.
   char tempPathBuffer[MAX_PATH];
   DWORD path_result = 0;
   path_result = GetTempPathA(MAX_PATH, tempPathBuffer);
   if (path_result > MAX_PATH || path_result == 0) return NULL;
   UINT name_result = 0;
   char tempNameBuffer[MAX_PATH];
   name_result = GetTempFileNameA(tempPathBuffer, "", 0, tempNameBuffer);
   if (name_result == 0) return NULL;
@@ skipping 788 matching lines @@
   DCHECK(result);
 }
 
 
 
 void Thread::YieldCPU() {
   Sleep(0);
 }
 
 } }  // namespace v8::base