__threading_support: fix windows build

The build was broken as there was no overload for long and
std::chrono::nanoseconds.  Add an explicit conversion to use the
operator+.

llvm-svn: 294698

1 files changed, 2 insertions, 1 deletions

diff --git a/libcxx/include/__threading_support b/libcxx/include/__threading_support
index b938d9c2b76..1e8be3fdab7 100644
--- a/libcxx/include/__threading_support
+++ b/libcxx/include/__threading_support
@@ -591,7 +591,8 @@ void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
 {
   using namespace chrono;
   // round-up to the nearest milisecond
-  milliseconds __ms = duration_cast<milliseconds>(__ns + 999999);
+  milliseconds __ms =
+      duration_cast<milliseconds>(__ns + chrono::nanoseconds(999999));
   Sleep(__ms.count());
 }