This change
1) Ensures that we only release files from tag/HEAD, not locally
modified ones.
2) Avoids disclosing personal data such as the username/group of the
local user.
3) Puts by default a umask of 0002, which turns off the world write bit
on files in the archive.
4) Avoids problems on some OSes (no more tar, git builtin tar.gz
handling).
Use the release tag if it exists or use HEAD.
This change 1) Ensures that we only release files from tag/HEAD, not locally modified ones. 2) Avoids disclosing personal data such as the username/group of the local user. 3) Puts by default a umask of 0002, which turns off the world write bit on files in the archive. 4) Avoids problems on some OSes (no more tar, git builtin tar.gz handling).