[gnome-control-center/gbsneto/g-gnuc-null-terminated] online-accounts: Mark run_goa_helper_sync as NULL-terminated

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit caa9b59f41c8742c6b7a5466c8c6dc4dd400e45a
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Jul 21 16:54:25 2022 -0300

    online-accounts: Mark run_goa_helper_sync as NULL-terminated
    
    Spotted while porting GNOME Initial Setup [1]
    
    [1]
    https://gitlab.gnome.org/GNOME/gnome-initial-setup/-/merge_requests/134

 panels/online-accounts/cc-online-accounts-panel.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/panels/online-accounts/cc-online-accounts-panel.c 
b/panels/online-accounts/cc-online-accounts-panel.c
index 6fc9d036d..2a626c27e 100644
--- a/panels/online-accounts/cc-online-accounts-panel.c
+++ b/panels/online-accounts/cc-online-accounts-panel.c
@@ -143,6 +143,7 @@ modify_row_for_account (CcOnlineAccountsPanel *self,
 
 /* Auxiliary methods */
 
+G_GNUC_NULL_TERMINATED
 static char *
 run_goa_helper_sync (const char *command,
                      ...)