Bug#118908: make TAGS does not work without having run configure

[Thomas Bushnell, BSG]

Roland McGrath <roland@gnu.org> writes:

> I have found tags in the generated stubs useful sometimes.  The old
> code gives you that, if you want to do make TAGS in a build
> directory.  We could do that in the configured case.  But I don't
> really care.

I think it's actually pretty important; we all know what's in the
generated stubs, but for a newbie, it can be pretty damn hard to
find.  So I think it's a good idea try and generate those too.