fixup! cygthread: suspend thread before terminating.

Suppress error output if ReadFile on child wait pipe returns
ERROR_OPERATION_ABORTED due to addition of CancelSynchronousIo call.

Cherry picked from commit eafd9a22bc (fixup! cygthread: suspend thread
before terminating., 2024-11-13) from msys2/msys2-runtime.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

winsup/cygwin/pinfo.cc

@@ -1262,13 +1262,14 @@ proc_waiter (void *arg)
 
   for (;;)
     {
-      DWORD nb;
+      DWORD nb, err;
       char buf = '\0';
 
       if (!ReadFile (vchild.rd_proc_pipe, &buf, 1, &nb, NULL)
-	  && GetLastError () != ERROR_BROKEN_PIPE)
+	  && (err = GetLastError ()) != ERROR_BROKEN_PIPE)
 	{
-	  system_printf ("error on read of child wait pipe %p, %E", vchild.rd_proc_pipe);
+	  if (err != ERROR_OPERATION_ABORTED)
+	    system_printf ("error on read of child wait pipe %p, %E", vchild.rd_proc_pipe);
 	  break;
 	}