This allows compilation with clang without errors, even when
-Wformat-nonliteral is active (as long as there are no real cases of
non literal formatting).
https://bugzilla.gnome.org/show_bug.cgi?id=691608
This is mostly complete, sans support for activation. However, its
not as picky as the libdbus implementation in terms like validation
and limits checking, nor is it as tested.
Its can be useful to test gdbus if dbus-daemon is not availible, but
its main reason for existance is to implement a default session bus
on win32 so that e.g. GApplication is guaranteed to work.
