We need to do this because constructors run before main() and
thus before any call to g_mem_set_vtable, making it impossible to
use that function if constructors call g_malloc.
We do this by making the constructors just register the static data
for lazy registration, doing the lazy registration when using
the global resource set.
GResource is a bundle of files combined into a single binary blog.
The API lets you access the files the resource contains by
using resource paths. You can also register resources with a
global list and access these globally in a merged resource namespace.
The normal way this is used is to link in the resources into your
application/library and have it be automatically registred.
Resources are compiled from an xml description using
glib-compile-resources.