Problems with fetching from GitHub using GH_TAGNAME= hash

[Kevin Oberman]

I an attempting to write a port for multimedia/mp4vs which has moved from
Google Code to GitHub. I tried specifying GH_TAGNAME= 6fda22f, but instead
of fetching mp4v2-Release-MP4v2-3.0.1.1.tar.gz, it tries to fetch
mp4v2-Release-MP4v2-3.0.1.1_GH0.tar.gz. (Note added "_GH0".)

I have no idea where this is coming from an have no experience with porting
where GitHub is the distfile repo.

My Makefile contains:
USE_GITHUB=     yes
GH_ACCOUNT=     TechSmith
GH_PROJECT=     mp4v2
GH_TAGNAME=     6fda22f

Any idea what I need to change?

Thanks,
--
Kevin Oberman, Part time kid herder and retired Network Engineer
E-mail: rkoberman at gmail.com
PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683