Build-Depends question re: yacc, ctags, etc.

[David Coe <david@someotherplace.org>]

If this has already been discussed, please just point me to it; I must
have missed it...

Yacc and ctags are provided by many different packages, and managed
by update-alternatives, but there is no virtual package corresponding
to either of them.

I suspect there are other similar situations.

I don't really want to say ``Build-Depends: bison, emacs20'', the
packages that happen to provide those for me, and it doesn't
feel right to list all the alternatives myself. 

And as far as I understand, these are not part of build-essentail or
any essential packages.  What should I do?  Thanks.