function compress_man_pages
Main purpose
- Decompress all man and info pages found in the package.
- Correct permissions.
- Re-compress them uniformly.
Notes
All man-pages and info pages are first uncompressed if needed. Then the
permissions of the uncompressed files are corrected and they are
re-compressed using the MAN_COMPRESS command. By default they are
compressed with gzip, but you can use MAN_COMPRESS=bzip2.
Some sources install pre-compressed man-pages and they may not be using
the same compression or have proper file permissions when uncompressed.
This is why everything is unpacked first and then recompressed.