Set a log domain to allow restricting debug output to Nemo only.

This eliminates having to enable all domains in order for Nemo's
debugging lines to print.

libnemo-private/nemo-action.c

@@ -2008,14 +2008,14 @@ nemo_action_update_display_state (NemoAction *action,
                                   GtkWindow  *window)
 {
     if (get_visibility (action, selection, parent, for_places, window)) {
-        DEBUG ("Action '%s' determined VISIBLE", gtk_action_get_name (GTK_ACTION (action)));
+        DEBUG ("Action '%s' determined VISIBLE", action->uuid);
 
         finalize_strings (action, selection, parent, window);
         gtk_action_set_visible (GTK_ACTION (action), TRUE);
 
         return;
     }
 
-    DEBUG ("Action '%s' determined HIDDEN", gtk_action_get_name (GTK_ACTION (action)));
+    DEBUG ("Action '%s' determined HIDDEN", action->uuid);
     gtk_action_set_visible (GTK_ACTION (action), FALSE);
 }

meson.build

@@ -180,6 +180,7 @@ nemo_definitions =  [
   '-DNEMO_DATADIR="@0@"'.format(nemoDataPath),
   '-DNEMO_EXTENSIONDIR="@0@"'.format(nemoExtensionPath),
   '-DLIBEXECDIR="@0@"'.format(libExecPath),
+  '-DG_LOG_DOMAIN="Nemo"'
 ]
 
 po_subdir = join_paths(meson.project_source_root(), 'po')

src/nemo-desktop-application.c

@@ -291,7 +291,8 @@ nemo_desktop_application_local_command_line (GApplication *application,
     }
 
     if (debug) {
-        g_setenv ("G_MESSAGES_DEBUG", "all", TRUE);
+        const gchar* const domains[] = { "Nemo", NULL };
+        g_log_writer_default_set_debug_domains (domains);
     }
 
     if (nemo_user_is_root () && !nemo_treating_root_as_normal ()) {

src/nemo-main-application.c

@@ -717,7 +717,8 @@ nemo_main_application_local_command_line (GApplication *application,
 	}
 
     if (debug) {
-        g_setenv ("G_MESSAGES_DEBUG", "all", TRUE);
+        const gchar* const domains[] = { "Nemo", NULL };
+        g_log_writer_default_set_debug_domains (domains);
     }
 
 	if (!do_cmdline_sanity_checks (self, perform_self_check,