pipewire: use elogind if systemd is disabled

Previously, logind functionality would be disabled if systemd was not found.
Since 1.2.5, PipeWire also supports building with elogind.  To minimize
variance between systemd enabled and not, let's use that for non-systemd
builds.

pkgs/development/libraries/pipewire/default.nix

@@ -4,6 +4,7 @@
 , python3
 , meson
 , ninja
+, elogind
 , systemd
 , enableSystemd ? true # enableSystemd=false maintained by maintainers.qyliss.
 , pkg-config
@@ -120,7 +121,7 @@ stdenv.mkDerivation(finalAttrs: {
     ncurses
     readline
     sbc
-  ] ++ (if enableSystemd then [ systemd ] else [ udev ])
+  ] ++ (if enableSystemd then [ systemd ] else [ elogind udev ])
   ++ (if lib.meta.availableOn stdenv.hostPlatform webrtc-audio-processing_1 then [ webrtc-audio-processing_1 ] else [ webrtc-audio-processing ])
   ++ lib.optional (lib.meta.availableOn stdenv.hostPlatform ldacbt) ldacbt
   ++ lib.optional zeroconfSupport avahi
@@ -146,6 +147,7 @@ stdenv.mkDerivation(finalAttrs: {
     (lib.mesonEnable "avahi" zeroconfSupport)
     (lib.mesonEnable "gstreamer" true)
     (lib.mesonEnable "gstreamer-device-provider" true)
+    (lib.mesonOption "logind-provider" (if enableSystemd then "libsystemd" else "libelogind"))
     (lib.mesonEnable "systemd" enableSystemd)
     (lib.mesonEnable "systemd-system-service" enableSystemd)
     (lib.mesonEnable "udev" (!enableSystemd))