In addition to the Makefile changes, we also change uid_t to gulong in
the public API (which matches how it was already represented in the
gobject properties).
https://bugzilla.gnome.org/show_bug.cgi?id=601458
We need to use the -lib variant which in turn uses the
GETTEXT_PACKAGE define, because the default translation
domain is actually mutter, not gnome-shell.
