build: Bring back compatibility with XApp 1.9.0

Dark Mode Manager is only a nice-to-have feature, not necessary.

This allows us to backport master versions of xreader to older
releases which ship xapp < 2.5.0.

Author: clefebvre

debian/control

@@ -19,7 +19,7 @@ Build-Depends: debhelper-compat (= 12),
                libsm-dev,
                libspectre-dev,
                libtiff-dev,
-               libxapp-dev (>= 2.5.0),
+               libxapp-dev (>= 1.9.0),
                libx11-dev,
                libxml2-dev,
                lsb-release,

meson.build

@@ -49,7 +49,10 @@ gtk_api_version = '3.0'
 gtk = dependency('gtk+-' + gtk_api_version, version: '>= ' + gtk_version)
 ice = dependency('ice')
 sm = dependency('sm')
-xapp = dependency('xapp', version: '>= 2.5.0')
+xapp = dependency('xapp', version: '>= 1.9.0')
+if xapp.version().version_compare('>= 2.6.0')
+    xreader_conf.set('HAVE_XAPP_DARK_MODE_MANAGER', 1)
+endif
 xml = dependency('libxml-2.0', version: '>= 2.5.0')
 zlib = dependency('zlib')
 libsecret = dependency('libsecret-1', version: '>= 0.5', required: get_option('keyring'))

shell/ev-application.c

@@ -60,7 +60,9 @@ struct _EvApplication {
 	guint                  scr_saver_cookie;
 	EggSMClient           *smclient;
 
+#ifdef HAVE_XAPP_DARK_MODE_MANAGER
     XAppDarkModeManager *dark_mode_manager;
+#endif
 };
 
 struct _EvApplicationClass {
@@ -902,9 +904,11 @@ ev_application_shutdown (GApplication *gapplication)
     g_free (application->dot_dir);
     application->dot_dir = NULL;
 
+#ifdef HAVE_XAPP_DARK_MODE_MANAGER
     if (application->dark_mode_manager) {
         g_clear_object (&application->dark_mode_manager);
     }
+#endif
 
     g_clear_pointer (&supported_mimetypes, g_strfreev);
 
@@ -1014,12 +1018,14 @@ ev_application_init (EvApplication *ev_application)
 
     parse_mimetypes ();
 
+#ifdef HAVE_XAPP_DARK_MODE_MANAGER
     if (g_strcmp0 (g_getenv ("XDG_CURRENT_DESKTOP"), "XFCE") != 0) {
         ev_application->dark_mode_manager = xapp_dark_mode_manager_new (FALSE);
     }
     else {
         ev_application->dark_mode_manager = NULL;
     }
+#endif
 }
 
 gboolean