In the unlikely case of stdin (fd 0) being closed, the off-by-one
would lead to pg_xlogdump failing to open files.
Spotted by Coverity.
Backpatch to 9.3 where pg_xlogdump was introduced.
This program relies on rm_desc backend routines and the xlogreader
infrastructure to emit human-readable rendering of WAL records.
Author: Andres Freund, with many reworks by Álvaro
Reviewed (in a much earlier version) by Peter Eisentraut