Fatal: Move up a variable to enable more reuse

Signed-off-by: Niels Thykier <niels@thykier.net>
Fatal: Remove a redundant if

Both paths basically compute the same end result.

Signed-off-by: Niels Thykier <niels@thykier.net>
Fatal: Rewrite/Reorder some comments

Signed-off-by: Niels Thykier <niels@thykier.net>
Fatal: Remove umask from ":default"

It is still included in older versions for compatability.  Note there
are no changes to documentation, since autodie apparently never
documented that is "protected" umask.

Closes #49

Signed-off-by: Niels Thykier <niels@thykier.net>
Fatal: Stop protecting fileno [RT#75199]

Signed-off-by: Niels Thykier <niels@thykier.net>
Changes: Document changes to fileno and umask

Signed-off-by: Niels Thykier <niels@thykier.net>