This macro will be used to mark these symbols as public exports. https://bugzilla.gnome.org/show_bug.cgi?id=688681
As pointed out by Christian Persch in bug 620173, all the new gdbus and gsettings headers were missing these.
Things compile and the test-suite passes. Still need to hook up gio.symbols and docs. There are still a bunch of TODOs left in the sources that needs to be addressed. Signed-off-by: David Zeuthen <davidz@redhat.com>