[gnome-session] (18 commits) ...NEWS: Add information about the new systemd user instance support

[Benjamin Berg <bberg src gnome org>]

Summary of changes:

  53cb8b5... gsm-systemd: Find user's graphical session, not the current (*)
  3f5c610... Add GNOME_SESSION_AUTOSTART_DIR variable to set the autosta (*)
  3b73720... autostart-app: Add X-GNOME-HiddenUnderSystemd for hiding (*)
  90fd993... fail-whale: Never show logout button in GDM (*)
  e8e9415... meson: Add compile time option to control systemd session m (*)
  8a91b9e... manager: Integrate with systemd startup notification (*)
  0e30c0f... util: Add API to start a systemd unit (*)
  98becaf... manager: Add systemd-managed property (*)
  d080265... manager: Allow fetching the configured session without mana (*)
  9b692a3... manager: Add initilization synchronization point DBus API (*)
  7ba953e... main: Add systemd gnome-session monitoring code for leader (*)
  922aa72... gnome-session-ctl: Add helper binary for systemd targets (*)
  0b4feda... data: Add systemd user units (*)
  cf86229... manager: Quit session manager after completing shutdown (*)
  7c7d16f... manager: Rely on systemd restarting DBus already (*)
  e6a94c3... main: Export autostart dir into environment (*)
  4d6ee3f... main: Enable systemd usage (*)
  514233a... NEWS: Add information about the new systemd user instance s (*)

(*) This commit already existed in another branch; no separate mail sent