* thread.h (pthread::static_cancel_self): Mark as noreturn.

(pthread::cancel_self): Ditto.
* thread.cc (pthread::cancel_self): Explicitly use pthread::exit to avoid a
"function returns" error.

winsup/cygwin/thread.cc

@@ -1044,7 +1044,9 @@ pthread::pop_all_cleanup_handlers ()
 void
 pthread::cancel_self ()
 {
-  exit (PTHREAD_CANCELED);
+  /* Can someone explain why the pthread:: is needed here?  g++ complains
+     without it. */
+  pthread::exit (PTHREAD_CANCELED);
 }
 
 DWORD