OS::TimeCurrentMillis should return double not long double

src/platform-posix.cc

Index: src/platform-posix.cc
diff --git a/src/platform-posix.cc b/src/platform-posix.cc
index 13b819bd1e79c1452979961fd082c2af73171e56..758e09d7a51bf3618e52fb3ea4856f138afaff58 100644
--- a/src/platform-posix.cc
+++ b/src/platform-posix.cc
@@ -320,8 +320,10 @@ int OS::GetUserTime(uint32_t* secs,  uint32_t* usecs) {
 double OS::TimeCurrentMillis() {
   struct timeval tv;
   if (gettimeofday(&tv, NULL) < 0) return 0.0;
-  return (static_cast<double>(tv.tv_sec) * 1000) +
-         (static_cast<double>(tv.tv_usec) / 1000);
+  volatile double result =
+      (static_cast<double>(tv.tv_sec) * 1000) +
+      (static_cast<double>(tv.tv_usec) / 1000);
+  return result;
 }