And if not the author, then the maintainer of the package
needs to handle versioning (perhaps YYYYMMDD).

Updates would be triggered by the maintainer changing that.

Quoting Thomas Klausner (wiz@NetBSD.org):
> On Sat, Dec 27, 2003 at 01:37:04PM -0700, Bruce J.A. Nourish wrote:
> > Is there an example of how to deal with unversioned source releases?
> > Basically, the source code is simply released as xxx-current.tgz,
> > which could be updated at any time. I'm thinking that perhaps the
> > installed package could get the name xxx-YYYMMDD. But then how
> > would updates (e.g. via pkg_chk) be handled?
> 
> The best way is to contact the author and to ask that he makes
> versioned distfiles -- he can always symlink/link/copy the latest
> to xxx-current.tgz.
> 
> The usual workaround is to do something like this:
> DISTNAME=	xxx-current.tgz
> PKGNAME=	xxx-20031227
> ...
> DIST_SUBDIR=	${PKGNAME_NOREV}
> ...
> 
>  Thomas