Changes in version 1.13:

The detection of bzip2 files with no compressed blocks has been fixed.
(Error introduced in version 1.9).

When zcat, zcmp, zdiff, or zgrep need to try compressed file names, gzip
(.gz) is now tried before bzip2 (.bz2).

When only one compressed file is passed to zcmp or zdiff, they now try to
compare it with a compressed file of any of the remaining formats if the
corresponding uncompressed file does not exist.

zcmp now reports EOF on empty file like GNU cmp:
"zcmp: EOF on FILE which is empty".

File diagnostics in zupdate have been reformatted as 'PROGRAM: FILE: MESSAGE'.

The variable MAKEINFO has been added to configure and Makefile.in.
