umask affects permissions in zkg bundles

[ekoyle]

The umask set by a user affects permissions of files on disk, which are then honored when creating the zkg bundle tarball. Setting a umask to something like 0027 is a good security practice, but can create bundles that cause problems in common zeek installations.

It would be very useful if zkg could create identical bundles regardless of a user's umask (or the permissions of the files on disk), or at least emit a warning if scripts aren't world readable when creating a bundle.