configure or patch gobject-introspection to include /usr/local in typelib search path

Ubuntu includes /usr/local/lib in the library search path via a file in /etc/ld.so.conf.d, and also configures pkg-config to look for .pc files in /usr/local/lib/pkgconfig. But gobject-introspection's built-in search path looks for type libraries only in /usr, not in /usr/local. That's inconsistent: I can install shared libraries in /usr/local and programs will find them, but their type libraries will not be found.

For consistency, I think Ubuntu should set the default gobject-introspection search path to include /usr/local/lib/girepository-1.0. It would be nice if gobject-introspection had a configure option that could set that (see https://bugzilla.gnome.org/show_bug.cgi?id=699331). In the meantime, it wouldn't be hard to patch gobject-introspection to set the default path; see init_globals() in girepository.c.