Move platform abstraction to base library

src/base/platform/platform-cygwin.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 Cygwin goes here. For the POSIX-compatible
 // parts, the implementation is in platform-posix.cc.
 
 #include <errno.h>
 #include <pthread.h>
 #include <semaphore.h>
 #include <stdarg.h>
 #include <strings.h>    // index
 #include <sys/mman.h>   // mmap & munmap
 #include <sys/time.h>
 #include <unistd.h>     // sysconf
 
 #include <cmath>
 
 #undef MAP_TYPE
 
+#include "src/base/macros.h"
+#include "src/base/platform/platform.h"
 #include "src/base/win32-headers.h"
-#include "src/platform.h"
-#include "src/utils.h"
 
 namespace v8 {
-namespace internal {
+namespace base {
 
 
 const char* OS::LocalTimezone(double time, TimezoneCache* cache) {
   if (std::isnan(time)) return "";
   time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
   struct tm* t = localtime(&tv);
   if (NULL == t) return "";
   return tzname[0];  // The location of the timezone string on Cygwin.
 }
 
@@ skipping 284 matching lines @@
 bool VirtualMemory::ReleaseRegion(void* base, size_t size) {
   return VirtualFree(base, 0, MEM_RELEASE) != 0;
 }
 
 
 bool VirtualMemory::HasLazyCommits() {
   // TODO(alph): implement for the platform.
   return false;
 }
 
-} }  // namespace v8::internal
+} }  // namespace v8::base