[age restriction] progress 8/n

More work towards support for extensions and age restriction

- updated gana
- added handler for DB-Event
- added TEH_extensions_init() and _done()
- added global for age restriction
- added stub for post handler
- added SQL-table for extension metadata
- added enum type for extensions and other data structures

Also:
- fixed some warnings -Wmaybe-unitialized

1 files changed, 3 insertions, 0 deletions

diff --git a/src/include/taler_exchangedb_plugin.h b/src/include/taler_exchangedb_plugin.h
index eacc13a9..6796fbac 100644
--- a/src/include/taler_exchangedb_plugin.h
+++ b/src/include/taler_exchangedb_plugin.h
@@ -4038,6 +4038,9 @@ struct TALER_EXCHANGEDB_Plugin
   enum GNUNET_DB_QueryStatus
   (*delete_revolving_shards)(void *cls);
 
+  /**
+   * TODO-oec: add function for adding extension config
+   */
 
 };