The main problem is that upstream provides unversioned auxiliary files
(htmlxref.cnf, texi2dvi and texinfo.tex) [1]. After several failure and PRs, I
decided to host those files in my LOCAL and use it as MASTER_SITES. It helps
make the update "expected". But it still makes problem when the users have an
outdated ports tree.
In order to solve this problem, those files are stored versioned (by date) in my
LOCAL from now on. Therefore, people with old ports tree would still be able to
fetch the files.
[1] https://ftp.gnu.org/gnu/texinfo/
