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.
To help cross compilation, don't use glib-genmarshal in our
build. This is easy now that we have g_cclosure_marshal_generic().
In gobject/, add gmarshal.[ch] to git (making the existing entry
points stubs).
In gio/, simply switch to using g_cclosure_marshal_generic().
https://bugzilla.gnome.org/show_bug.cgi?id=652168
This adds an extension point for TLS connections to gio, with a
gnutls-based implementation in glib-networking.
Full TLS support is still a work in progress; the current API is
missing some features, and parts of it may still be changed before
2.28.
https://bugzilla.gnome.org/show_bug.cgi?id=588189
