Add explicit cast to non-apple platforms

Author: mhegazy

stdlib/public/Concurrency/DispatchGlobalExecutor.cpp

@@ -314,11 +314,6 @@ clock_and_value_to_time(int clock, long long sec, long long nsec) {
   case swift_clock_id_continuous:
     return value | DISPATCH_UP_OR_MONOTONIC_TIME_MASK;
   case swift_clock_id_wall: {
-#if defined(_WIN32)
-    struct timespec ts = { 
-      .tv_sec = sec,
-      .tv_nsec = static_cast<long>(nsec)
-    };
 #elif defined(__APPLE__)
     struct timespec ts = { 
       .tv_sec = static_cast<__darwin_time_t>(sec),
@@ -327,7 +322,7 @@ clock_and_value_to_time(int clock, long long sec, long long nsec) {
 #else
     struct timespec ts = { 
       .tv_sec = static_cast<long>(sec),
-      .tv_nsec = nsec
+      .tv_nsec = static_cast<long>(nsec)
     };
 #endif
     return dispatch_walltime(&ts, 0);