* exceptions.cc (call_handler): Use new muto linked list to look for all

potential mutos owned by suspended thread.  Clear waiting threads while thread
is stopped.
(proc_subproc): Clarify debugging output.
* sync.h (class muto): Add 'next' field.
(new_muto): Keep linked list alive.

winsup/cygwin/sigproc.cc

@@ -333,7 +333,10 @@ proc_subproc (DWORD what, DWORD val)
      */
     case PROC_CLEARWAIT:
       /* Clear all "wait"ing threads. */
-      sip_printf ("clear waiting threads");
+      if (val)
+	sip_printf ("clear waiting threads");
+      else
+	sip_printf ("looking for processes to reap");
       clearing = val;
 
     scan_wait: