The spec removes $RPM_BUILD_ROOT%{_libdir}/*.la, but misses $RPM_BUILD_ROOT%{_libdir}/gtk-2.0/2.4.0/immodules/*.la and $RPM_BUILD_ROOT%{_libdir}/gtk-2.0/2.4.0/loaders/*.la This isn't so bad because nothing will ever link to them directly, but they're still a waste of disk space.
Fixed in 2.4.10-2, should appear in rawhide soon.