Increase likelihood that budgie-desktop is being shipped with require…

…d component.

budgie-screensaver, our fork of gnome-screensaver, is required for locker functionality as of Budgie 10.5.3 due to changes in GNOME Settings Daemon and GNOME Shell (which affects the use of gdm + future locking as gnome-shell will register and keep the ScreenSaver bus, only killable via our budgie-screensaver v4 changes).

This patch introduces org.gnome.desktop.screensaver Budgie session override per suggestion from #2124 as well.

meson.build

@@ -11,6 +11,17 @@ project(
     ],
 )
 
+budgie_screensaver  = find_program('budgie-screensaver', required: false)
+assert(budgie_screensaver.found(), 'Budgie Screensaver is a required separate component of Budgie Desktop. Please ensure budgie-screensaver is available at configure and run time. You can find this at https://github.com/getsolus/budgie-screensaver')
+
+if budgie_screensaver.found()
+    budgie_screensaver_version_cmd = run_command('budgie-screensaver', ['--version'])
+    cmd_out = budgie_screensaver_version_cmd.stdout()
+    split_cmd = cmd_out.split(' ')
+    budgie_screensaver_version = split_cmd.get(1)
+    assert(budgie_screensaver_version.version_compare('>=4.0'), 'Budgie Screensaver must be 4.0 or higher. Found @0@'.format(budgie_screensaver_version))
+endif
+
 git = find_program('git', required: false)
 
 am_cflags = [

src/wm/20_solus-project.budgie.wm.gschema.override

@@ -8,3 +8,5 @@ picture-uri = 'file:///usr/share/backgrounds/budgie/default.jpg'
 [org.gnome.desktop.wm.preferences:Budgie]
 button-layout = 'appmenu:minimize,maximize,close'
 
+[org.gnome.desktop.screensaver:Budgie]
+picture-uri = 'file:///usr/share/backgrounds/budgie/default.jpg'