Fix polling for input data on the master side of a PTY

src/main.rs

@@ -198,7 +198,7 @@ impl Pty {
     fn curr_master_poll(&self) -> PollEvents {
         let mut events = PollEvents::POLLOUT;
         if !self.output_buffer.lock().is_empty() {
-            events |= PollEvents::POLLOUT;
+            events |= PollEvents::POLLIN;
         }
         events
     }