In its previous form, g_settings_list_schemas() was not useful as a tool
to prevent aborts due to using g_settings_new() with an invalid schema
name. This is because g_settings_list_scheams() also listed relocatable
schemas, and calling g_settings_new() for those would abort just the
same as if you called it for a non-existent schema.
Modify g_settings_list_schemas() so that it only returns schemas for
which it is safe to call g_settings_new(). Add another call for sake of
completeness: g_settings_list_relocatable_schemas().
gvdb just dropped the ability to have a separate "options" field. We
now store the options into a GVariant along with the default value.
For now, we use a small shim in GSettingsSchema in order not to touch
too much code. A more complete rewrite will follow.
This represents a change to the schema file format with another likely
to follow. glib-compile-schemas needs to be re-run after installing
this change.
