improved sshd child monitor code to avoid annoying "broken pipe" msg from Linux clients

take child detection handle out from select mux after a child process is
detected to have exited so that other code exit handlings can run its
course

Author: quamrulmina

contrib/win32/win32compat/socket.c

@@ -1994,6 +1994,13 @@ int WSHELPAddChildToWatch ( HANDLE processtowatch)
 	return 0;
 }
 
+int WSHELPDelChildToWatch ( HANDLE processtowatch)
+{
+	if ( ChildToWatch == processtowatch )
+		ChildToWatch = NULL ;
+	return 0;
+}
+
 int WSHELPselect(int fds, fd_set* readsfds, fd_set* writesfds,
                      fd_set* exceptsfds, const struct timeval* timeout)
 {

serverloop.c

@@ -879,6 +879,8 @@ collect_children(void)
         session_close_by_pid(s->pid, status);
 
         CloseHandle(process);
+		int WSHELPDelChildToWatch (HANDLE processtowatch);
+		WSHELPDelChildToWatch (process); // take the process off from watch list in select mux
       }
     }
   } while (i > 0);