fix build on windows

mux/src/localpane.rs

@@ -458,10 +458,18 @@ impl Pane for LocalPane {
     }
 
     fn tty_name(&self) -> Option<String> {
+        #[cfg(unix)]
+        {
             let name = self.pty.lock().tty_name()?;
             Some(name.to_string_lossy().into_owned())
         }
 
+        #[cfg(windows)]
+        {
+            None
+        }
+    }
+
     fn get_foreground_process_info(&self) -> Option<LocalProcessInfo> {
         #[cfg(unix)]
         if let Some(pid) = self.pty.lock().process_group_leader() {