master c0ced4e499: Prevent setting user time if the WM doesn't support it

[Po Lu]

branch: master
commit c0ced4e49989b98035729b46693a56c5f168d8bf
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Prevent setting user time if the WM doesn't support it
    
    * src/xterm.c (x_update_frame_user_time_window): Don't set
    _NET_WM_USER_TIME if it's not supported by the window manager.
---
 src/xterm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/xterm.c b/src/xterm.c
index 39ce415472..2b83efb228 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -7117,7 +7117,8 @@ x_update_frame_user_time_window (struct frame *f)
   output = FRAME_X_OUTPUT (f);
   dpyinfo = FRAME_DISPLAY_INFO (f);
 
-  if (!NILP (Vx_no_window_manager))
+  if (!NILP (Vx_no_window_manager)
+      || !x_wm_supports (f, dpyinfo->Xatom_net_wm_user_time))
     {
       if (output->user_time_window != None
          && output->user_time_window != FRAME_OUTER_WINDOW (f))