Problems with updating a port due to top directory in tarball

[Hiroo Ono]

On 2021年3月4日木曜日 9時00分32秒 JST, Kevin Oberman wrote:
> I'm trying to update a port I maintain. Since I last updated, it moved from
> ISC to github and it uses unusual naming conventions.
>
> The distfile is "irrtoolset/archive/release-5.1.3.tar.gz". I can work
> around this with a DIST_SUBDIR and DISTNAME, but when the extract takes
> place,  the top directory in the tarball is "irrtoolset-release-5.1.3".
> Since this is not expected, patch fails.

If it is same as what is tagged as "release-5.1.3",

DISTVERSIONPREFIX=	release-
DISTVERSION=	5.1.3
USE_GITHUB=	yes
GH_ACCOUNT=	irrtoolset
GH_PROJECT=	irrtoolset

should work.
cf. 
https://docs.freebsd.org/en_US.ISO8859-1/books/porters-handbook/makefile-distfiles.html#makefile-master_sites-github-description