Better handling of Wayland compositors (#1539)

* Better handling of Wayland compositors

* Reinstate setting ps_flags, it's used elsewhere

* Try another incantation

* Try another incantation

* Try another incantation

* Use short options and a newline to reduce line-length

* Rework to handle the "better way" failing on some systems and fall back to the old method (which has the virtue of working most of the time).

neofetch

@@ -1815,7 +1815,14 @@ get_wm() {
         *)         ps_flags=(-e) ;;
     esac
 
-    if [[ $WAYLAND_DISPLAY ]]; then
+    if [[ -O "${XDG_RUNTIME_DIR}/${WAYLAND_DISPLAY:-wayland-0}" ]]; then
+        if tmp_pid="$(lsof -t "${XDG_RUNTIME_DIR}/${WAYLAND_DISPLAY:-wayland-0}" 2>&1)" ||
+           tmp_pid="$(fuser   "${XDG_RUNTIME_DIR}/${WAYLAND_DISPLAY:-wayland-0}" 2>&1)"; then
+            wm="$(ps -p "${tmp_pid}" -ho comm=)"
+        else
+            # lsof may not exist, or may need root on some systems. Similarly fuser.
+            # On those systems we search for a list of known window managers, this can mistakenly
+            # match processes for another user or session and will miss unlisted window managers.
             wm=$(ps "${ps_flags[@]}" | grep -m 1 -o -F \
                                -e arcan \
                                -e asc \
@@ -1844,6 +1851,7 @@ get_wm() {
                                -e westeros \
                                -e westford \
                                -e weston)
+        fi
 
     elif [[ $DISPLAY && $os != "Mac OS X" && $os != "macOS" && $os != FreeMiNT ]]; then
         type -p xprop &>/dev/null && {