* cygwait.cc (cygwait): Remove lock around sig retrieval since this code is

essentially guarded by thread-specific signal_arrived.
* exceptions.cc (_cygtls::handle_SIGCONT): Simplify.  Eliminate lock/unlock
since code is guarded by signal_arrived.

winsup/cygwin/miscfuncs.cc

@@ -251,10 +251,8 @@ yield ()
       /* MSDN implies that SleepEx will force scheduling of other threads.
 	 Unlike SwitchToThread() the documentation does not mention other
 	 cpus so, presumably (hah!), this + using a lower priority will
-	 stall this thread temporarily and cause another to run.
-	 Note: Don't use 0 timeout.  This takes a lot of CPU if something
-	 goes wrong. */
-      SleepEx (1L, false);
+	 stall this thread temporarily and cause another to run.  */
+      SleepEx (0L, false);
     }
   SetThreadPriority (GetCurrentThread (), prio);
 }