(empth_sleep) [_WIN32]: Change if to while to ensure the time has

actually been reached.  There has been examples where the time
expired early by one second probably due a resolution error.  This
caused a scheduled update to be missed.  Broken in rev. 1.56.

src/lib/empthread/ntthread.c

@@ -601,7 +601,7 @@ empth_sleep(time_t until)
     empth_t *pThread = TlsGetValue(dwTLSIndex);
     int iReturn = 0;
 
-    if ((lSec = until - time(0)) > 0) {
+    while (!iReturn && ((lSec = until - time(0)) > 0)) {
 	loc_BlockThisThread();
 	loc_debug("going to sleep %ld sec", lSec);