master d37ba6f259: Fix killing Emacs upon display disconnect

[Po Lu]

branch: master
commit d37ba6f259b972aa44c66ecb76210e03a3084183
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Fix killing Emacs upon display disconnect
    
    * src/xterm.c (x_connection_closed): On Xt builds terminals can
    be left alive without any frames on them, so take that into
    account.  (bug#56528)
---
 src/xterm.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/xterm.c b/src/xterm.c
index 3dfbe111d3..1d0e69d32b 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -23531,7 +23531,11 @@ For details, see etc/PROBLEMS.\n",
 
   unblock_input ();
 
-  if (terminal_list == 0)
+  /* Sometimes another terminal is still alive, but deleting this
+     terminal caused all frames to vanish.  In that case, simply kill
+     Emacs, since the next redisplay will abort as there is no more
+     selected frame.  (bug#56528) */
+  if (terminal_list == 0 || NILP (selected_frame))
     Fkill_emacs (make_fixnum (70), Qnil);
 
   totally_unblock_input ();