Start up in daemon mode when GNOME starts

Hat tip to Guido for the session.{c,h} files.

Closes #45

data/meson.build

@@ -1,8 +1,12 @@
 datadir = get_option('datadir')
+sysconfdir = get_option('sysconfdir')
 
 # Desktop file
 install_data('sm.puri.Calls.desktop',
              install_dir : join_paths(datadir, 'applications'))
+install_data('sm.puri.Calls-daemon.desktop',
+             rename : 'sm.puri.Calls.desktop',
+             install_dir : join_paths(sysconfdir, 'xdg/autostart'))
 
 desktop_utils = find_program('desktop-file-validate', required: false)
 if desktop_utils.found()
@@ -10,6 +14,10 @@ if desktop_utils.found()
        args: [join_paths(meson.current_source_dir(),
                          'sm.puri.Calls.desktop')
              ])
+  test('Validate daemon desktop file', desktop_utils,
+       args: [join_paths(meson.current_source_dir(),
+                         'sm.puri.Calls-daemon.desktop')
+             ])
 endif
 
 # Appdata file

data/sm.puri.Calls-daemon.desktop

@@ -0,0 +1,16 @@
+[Desktop Entry]
+Name=Calls (daemon)
+GenericName=Phone
+Comment=A phone dialer and call handler (daemon mode)
+# Translators: These are desktop search terms. Do not translate semicolons, end line with a semicolon.
+Keywords=Telephone;Call;Phone;Dial;Dialer;PTSN;
+# Translators: Do NOT translate or transliterate this text (this is an icon file name)!
+Icon=sm.puri.Calls
+TryExec=calls
+Exec=calls --daemon
+Type=Application
+StartupNotify=true
+NoDisplay=true
+Terminal=false
+Categories=GNOME;GTK;Telephony;
+X-GNOME-AutoRestart=true