Update sysutils/fdupes to 1.51

Patch via pkgsrc-wip/fdupes by Mateusz Poszwa

Changes from 1.50 to 1.51

- Added support for 64-bit file offsets on 32-bit systems.
- Using tty for interactive input instead of regular stdin. This is to
  allow  feeding filenames via stdin in future versions of fdupes without
  breaking interactive deletion feature.
- Fixed some typos in --help.
- Turned C++ style comments into C style comments.

Changes from 1.40 to 1.50-PR2

- Fixed memory leak. [JB]
- Added "--summarize" option. [AL]
- Added "--recurse:" selective recursion option. [AL]
- Added "--noprompt" option for totally automated deletion of
  duplicate files.
- Now sorts duplicates (old to new) for consistent order when
  listing or deleteing duplicate files.
- Now tests for early matching of files, which should help speed up
  the matching process when large files are involved.
- Added warning whenever a file cannot be deleted. [CHL, AL]
- Fixed bug where some files would not be closed after failure. [AL]
- Fixed bug where confirmmatch() function wouldn't always deal
  properly with zero-length files. [AL]
- Fixed bug where progress indicator would not be cleared
  when no files were found. [AL]
- Removed experimental red-black tree code (it was slower on
  my system than the default code). [AL]
- Modified md5/md5.c to avoid compiler warning. [CHL]
- Changes to fdupes.c for compilation under platforms where
  getopt_long is unavailable. [LR, AL]
- Changes to help text for clarity. [AL]
- Various changes and improvements to Makefile. [PB, AL]

(kamil)