If we have an input parameter (or return value) we need to use (nullable).
However, if it is an (inout) or (out) parameter, (optional) is sufficient.
It looks like (nullable) could be used for everything according to the
Annotation documentation, but (optional) is more specific.
Since all element markup is now gone from the doc comments,
we can turn off the gtk-doc sgml mode, which means that from
now on, docbook markup is no longer allowed in doc comments.
To make this possible, we have to replace all remaining
entities in doc comments by their replacement text, & -> &
and so on.
Add _g_io_module_get_default(), which implements the
figure-out-the-best-available-module-that-is-actually-usable logic,
and use that to simplify g_proxy_resolver_get_default(),
g_settings_backend_get_default(), g_tls_backend_get_default(), and
g_vfs_get_default().
https://bugzilla.gnome.org/show_bug.cgi?id=620932
This extension point allow extending GLib with library like LibProxy that
interprets system proxy settings and finds the appropriate configuration
based on the type of connection being made.
Reviewed-by: Dan Winship <danw@gnome.org>
