* lib-src/emacsclient.c (set_local_socket): Revert to the Emacs 27 behavior of not trying TMPDIR if XDG_RUNTIME_DIR is set. This is one of the suggestions made by Jim Porter and independently by Ulrich Mueller in Bug#51327.
This directory contains the source code for the architecture-dependent
files that go in ${archlibdir}. At present, these are mostly utility
programs used by GNU Emacs.