Fixes https://github.com/termux/termux-packages/issues/10220.

--- a/sesman/session.c
+++ b/sesman/session.c
@@ -768,8 +768,11 @@
                     list_add_item(xserver_params, (tintptr)g_strdup(geometry));
                     list_add_item(xserver_params, (tintptr)g_strdup("-depth"));
                     list_add_item(xserver_params, (tintptr)g_strdup(depth));
-                    list_add_item(xserver_params, (tintptr)g_strdup("-rfbauth"));
-                    list_add_item(xserver_params, (tintptr)g_strdup(passwd_file));
+                    if (passwd_file != 0 && *passwd_file != '\0')
+                    {
+                        list_add_item(xserver_params, (tintptr)g_strdup("-rfbauth"));
+                        list_add_item(xserver_params, (tintptr)g_strdup(passwd_file));
+                    }
 
                     g_free(passwd_file);