[base] Use thread safe localtime_r() instead of localtime().

src/base/platform/platform-openbsd.cc

Index: src/base/platform/platform-openbsd.cc
diff --git a/src/base/platform/platform-openbsd.cc b/src/base/platform/platform-openbsd.cc
index af145e2fca117696950108c4e04f2c530e0ccf8a..6ecf1f12ba7286b2d1bd3a3ab7644c3c73a043f8 100644
--- a/src/base/platform/platform-openbsd.cc
+++ b/src/base/platform/platform-openbsd.cc
@@ -37,7 +37,8 @@ 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);  // NOLINT(runtime/threadsafe_fn)
+  struct tm tm;
+  struct tm* t = localtime_r(&tv, &tm);
   if (NULL == t) return "";
   return t->tm_zone;
 }
@@ -45,7 +46,8 @@ const char* OS::LocalTimezone(double time, TimezoneCache* cache) {
 
 double OS::LocalTimeOffset(TimezoneCache* cache) {
   time_t tv = time(NULL);
-  struct tm* t = localtime(&tv);  // NOLINT(runtime/threadsafe_fn)
+  struct tm tm;
+  struct tm* t = localtime_r(&tv, &tm);
   // tm_gmtoff includes any daylight savings offset, so subtract it.
   return static_cast<double>(t->tm_gmtoff * msPerSecond -
                              (t->tm_isdst > 0 ? 3600 * msPerSecond : 0));