emacsclient: prefer XDG_RUNTIME_DIR (Bug#33367)

* lib-src/emacsclient.c: Disable -Wformat-truncation=2,
to avoid false alarms about the new snprintf calls.
(local_sockname): New function.
(set_local_socket): Use it.  Prefer XDG_RUNTIME_DIR (if set)
for location of socket directory.  Avoid unnecessary memory
allocation by using snprintf to destination.
* lisp/server.el (server-socket-dir): Prefer XDG_RUNTIME_DIR if set.

1 files changed, 4 insertions, 1 deletions

diff --git a/lisp/server.el b/lisp/server.el
index d0a8ca313e3..28e789a4c88 100644
--- a/lisp/server.el
+++ b/lisp/server.el
@@ -281,7 +281,10 @@ changed while a server is running."
   (if internal--daemon-sockname
       (file-name-directory internal--daemon-sockname)
     (and (featurep 'make-network-process '(:family local))
-         (format "%s/emacs%d" (or (getenv "TMPDIR") "/tmp") (user-uid))))
+         (let ((xdg_runtime_dir (getenv "XDG_RUNTIME_DIR")))
+           (if xdg_runtime_dir
+               (format "%s/emacs" xdg_runtime_dir)
+             (format "%s/emacs%d" (or (getenv "TMPDIR") "/tmp") (user-uid))))))
   "The directory in which to place the server socket.
 If local sockets are not supported, this is nil.")