Move the macro and declaration so it can use glib in the following
patch (it already depends on glib anyway for !optimize)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220420132624.2439741-19-marcandre.lureau@redhat.com>