Fix a race in initialization of timezone cache in platform-win32.

src/platform-posix.cc

Index: src/platform-posix.cc
diff --git a/src/platform-posix.cc b/src/platform-posix.cc
index 94aabe8d581101fc08ffb95298de55cf3625c89d..cb93d81f9e4207baeaf58f9627181641c7501b7d 100644
--- a/src/platform-posix.cc
+++ b/src/platform-posix.cc
@@ -354,7 +354,25 @@ double OS::TimeCurrentMillis() {
 }
 
 
-double OS::DaylightSavingsOffset(double time) {
+class TimezoneCache {};
+
+
+TimezoneCache* OS::CreateTimezoneCache() {
+  return NULL;
+}
+
+
+void OS::DisposeTimezoneCache(TimezoneCache* cache) {
+  ASSERT(cache == NULL);
+}
+
+
+void OS::ClearTimezoneCache(TimezoneCache* cache) {
+  ASSERT(cache == NULL);
+}
+
+
+double OS::DaylightSavingsOffset(double time, TimezoneCache*) {
   if (std::isnan(time)) return nan_value();
   time_t tv = static_cast<time_t>(std::floor(time/msPerSecond));
   struct tm* t = localtime(&tv);
@@ -363,9 +381,6 @@ double OS::DaylightSavingsOffset(double time) {
 }
 
 
-void OS::TimeZoneChanged() {}
-
-
 int OS::GetLastError() {
   return errno;
 }