version tags

[Ross Paterson]

On Fri, May 09, 2008 at 10:12:06AM +0100, Duncan Coutts wrote:
> It's clear we should drop the check on the tags from the == test but I'm
> not sure if we should also change the showVersion or parseVersion
> functions.
> 
> I'm planning on changing the equivalent of showVersion in Cabal to not
> display the tags.

What are tags for?  Should we have them at all?

Currently they've been used in:

	hsgnutls-0.2.3-barracuda
	hsgnutls-0.2.3.1-barracuda
	regex-tdfa-0.92-ghc-68-build-fix

which seem to be non-maintainer releases.  You'd want such versions to
be distinguished from the untagged versions.